[v7] libgfortran: Replace mutex with rwlock
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Commit Message
This patch try to introduce the rwlock and split the read/write to
unit_root tree and unit_cache with rwlock instead of the mutex to
increase CPU efficiency. In the get_gfc_unit function, the percentage
to step into the insert_unit function is around 30%, in most instances,
we can get the unit in the phase of reading the unit_cache or unit_root
tree. So split the read/write phase by rwlock would be an approach to
make it more parallel.
BTW, the IPC metrics can gain around 9x in our test
server with 220 cores. The benchmark we used is
https://github.com/rwesson/NEAT
libgcc/ChangeLog:
* gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
(__gthrw): New function.
(__gthread_rwlock_rdlock): New function.
(__gthread_rwlock_tryrdlock): New function.
(__gthread_rwlock_wrlock): New function.
(__gthread_rwlock_trywrlock): New function.
(__gthread_rwlock_unlock): New function.
libgfortran/ChangeLog:
* io/async.c (DEBUG_LINE): New macro.
* io/async.h (RWLOCK_DEBUG_ADD): New macro.
(CHECK_RDLOCK): New macro.
(CHECK_WRLOCK): New macro.
(TAIL_RWLOCK_DEBUG_QUEUE): New macro.
(IN_RWLOCK_DEBUG_QUEUE): New macro.
(RDLOCK): New macro.
(WRLOCK): New macro.
(RWUNLOCK): New macro.
(RD_TO_WRLOCK): New macro.
(INTERN_RDLOCK): New macro.
(INTERN_WRLOCK): New macro.
(INTERN_RWUNLOCK): New macro.
* io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
a comment.
(unit_lock): Remove including associated internal_proto.
(unit_rwlock): New declarations including associated internal_proto.
(dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
instead of __gthread_mutex_lock and __gthread_mutex_unlock on
unit_lock.
* io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
unit_rwlock instead of LOCK and UNLOCK on unit_lock.
(st_write_done_worker): Likewise.
* io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
comment. Use unit_rwlock variable instead of unit_lock variable.
(get_gfc_unit_from_unit_root): New function.
(get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
instead of LOCK and UNLOCK on unit_lock.
(close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
LOCK and UNLOCK on unit_lock.
(close_units): Likewise.
(newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
unit_lock.
* io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
instead of LOCK and UNLOCK on unit_lock.
(flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
of LOCK and UNLOCK on unit_lock.
---
v1 -> v2:
Limit the pthread_rwlock usage in libgcc only when __cplusplus isn't defined.
v2 -> v3:
Rebase the patch with trunk branch.
v3 -> v4:
Update the comments.
v4 -> v5:
Fix typos and code formatter.
v5 -> v6:
Add unit tests.
v6 -> v7:
Update ChangeLog and code formatter.
Reviewed-by: Hongjiu Lu <hongjiu.lu@intel.com>
Reviewed-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
Reviewed-by: Thomas Koenig <tkoenig@netcologne.de>
Reviewed-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: Lipeng Zhu <lipeng.zhu@intel.com>
---
libgcc/gthr-posix.h | 60 +++++++
libgfortran/io/async.c | 4 +
libgfortran/io/async.h | 151 ++++++++++++++++++
libgfortran/io/io.h | 15 +-
libgfortran/io/transfer.c | 8 +-
libgfortran/io/unit.c | 117 +++++++++-----
libgfortran/io/unix.c | 16 +-
.../testsuite/libgomp.fortran/rwlock_1.f90 | 33 ++++
.../testsuite/libgomp.fortran/rwlock_2.f90 | 22 +++
.../testsuite/libgomp.fortran/rwlock_3.f90 | 18 +++
10 files changed, 386 insertions(+), 58 deletions(-)
create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_1.f90
create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_2.f90
create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_3.f90
Comments
On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
> This patch try to introduce the rwlock and split the read/write to
> unit_root tree and unit_cache with rwlock instead of the mutex to
> increase CPU efficiency. In the get_gfc_unit function, the percentage
> to step into the insert_unit function is around 30%, in most instances,
> we can get the unit in the phase of reading the unit_cache or unit_root
> tree. So split the read/write phase by rwlock would be an approach to
> make it more parallel.
>
> BTW, the IPC metrics can gain around 9x in our test
> server with 220 cores. The benchmark we used is
> https://github.com/rwesson/NEAT
>
> libgcc/ChangeLog:
>
> * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
> (__gthrw): New function.
> (__gthread_rwlock_rdlock): New function.
> (__gthread_rwlock_tryrdlock): New function.
> (__gthread_rwlock_wrlock): New function.
> (__gthread_rwlock_trywrlock): New function.
> (__gthread_rwlock_unlock): New function.
>
> libgfortran/ChangeLog:
>
> * io/async.c (DEBUG_LINE): New macro.
> * io/async.h (RWLOCK_DEBUG_ADD): New macro.
> (CHECK_RDLOCK): New macro.
> (CHECK_WRLOCK): New macro.
> (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
> (IN_RWLOCK_DEBUG_QUEUE): New macro.
> (RDLOCK): New macro.
> (WRLOCK): New macro.
> (RWUNLOCK): New macro.
> (RD_TO_WRLOCK): New macro.
> (INTERN_RDLOCK): New macro.
> (INTERN_WRLOCK): New macro.
> (INTERN_RWUNLOCK): New macro.
> * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
> a comment.
> (unit_lock): Remove including associated internal_proto.
> (unit_rwlock): New declarations including associated internal_proto.
> (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
> instead of __gthread_mutex_lock and __gthread_mutex_unlock on
> unit_lock.
> * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
> unit_rwlock instead of LOCK and UNLOCK on unit_lock.
> (st_write_done_worker): Likewise.
> * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
> comment. Use unit_rwlock variable instead of unit_lock variable.
> (get_gfc_unit_from_unit_root): New function.
> (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
> instead of LOCK and UNLOCK on unit_lock.
> (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
> LOCK and UNLOCK on unit_lock.
> (close_units): Likewise.
> (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
> unit_lock.
> * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
> instead of LOCK and UNLOCK on unit_lock.
> (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> of LOCK and UNLOCK on unit_lock.
Ok for trunk, thanks.
Jakub
On 2023/12/9 23:23, Jakub Jelinek wrote:
> On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
> > This patch try to introduce the rwlock and split the read/write to
> > unit_root tree and unit_cache with rwlock instead of the mutex to
> > increase CPU efficiency. In the get_gfc_unit function, the percentage
> > to step into the insert_unit function is around 30%, in most
> > instances, we can get the unit in the phase of reading the unit_cache
> > or unit_root tree. So split the read/write phase by rwlock would be an
> > approach to make it more parallel.
> >
> > BTW, the IPC metrics can gain around 9x in our test server with 220
> > cores. The benchmark we used is https://github.com/rwesson/NEAT
> >
> > libgcc/ChangeLog:
> >
> > * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
> > (__gthrw): New function.
> > (__gthread_rwlock_rdlock): New function.
> > (__gthread_rwlock_tryrdlock): New function.
> > (__gthread_rwlock_wrlock): New function.
> > (__gthread_rwlock_trywrlock): New function.
> > (__gthread_rwlock_unlock): New function.
> >
> > libgfortran/ChangeLog:
> >
> > * io/async.c (DEBUG_LINE): New macro.
> > * io/async.h (RWLOCK_DEBUG_ADD): New macro.
> > (CHECK_RDLOCK): New macro.
> > (CHECK_WRLOCK): New macro.
> > (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
> > (IN_RWLOCK_DEBUG_QUEUE): New macro.
> > (RDLOCK): New macro.
> > (WRLOCK): New macro.
> > (RWUNLOCK): New macro.
> > (RD_TO_WRLOCK): New macro.
> > (INTERN_RDLOCK): New macro.
> > (INTERN_WRLOCK): New macro.
> > (INTERN_RWUNLOCK): New macro.
> > * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
> > a comment.
> > (unit_lock): Remove including associated internal_proto.
> > (unit_rwlock): New declarations including associated internal_proto.
> > (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
> > instead of __gthread_mutex_lock and __gthread_mutex_unlock on
> > unit_lock.
> > * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK
> on
> > unit_rwlock instead of LOCK and UNLOCK on unit_lock.
> > (st_write_done_worker): Likewise.
> > * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
> > comment. Use unit_rwlock variable instead of unit_lock variable.
> > (get_gfc_unit_from_unit_root): New function.
> > (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
> > instead of LOCK and UNLOCK on unit_lock.
> > (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> of
> > LOCK and UNLOCK on unit_lock.
> > (close_units): Likewise.
> > (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
> > unit_lock.
> > * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
> > instead of LOCK and UNLOCK on unit_lock.
> > (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> > of LOCK and UNLOCK on unit_lock.
>
> Ok for trunk, thanks.
>
> Jakub
Thanks! Looking forward to landing to trunk.
Lipeng Zhu
On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
>
> On 2023/12/9 23:23, Jakub Jelinek wrote:
> > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
> > > This patch try to introduce the rwlock and split the read/write to
> > > unit_root tree and unit_cache with rwlock instead of the mutex to
> > > increase CPU efficiency. In the get_gfc_unit function, the percentage
> > > to step into the insert_unit function is around 30%, in most
> > > instances, we can get the unit in the phase of reading the unit_cache
> > > or unit_root tree. So split the read/write phase by rwlock would be an
> > > approach to make it more parallel.
> > >
> > > BTW, the IPC metrics can gain around 9x in our test server with 220
> > > cores. The benchmark we used is https://github.com/rwesson/NEAT
> > >
> > > libgcc/ChangeLog:
> > >
> > > * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
> > > (__gthrw): New function.
> > > (__gthread_rwlock_rdlock): New function.
> > > (__gthread_rwlock_tryrdlock): New function.
> > > (__gthread_rwlock_wrlock): New function.
> > > (__gthread_rwlock_trywrlock): New function.
> > > (__gthread_rwlock_unlock): New function.
> > >
> > > libgfortran/ChangeLog:
> > >
> > > * io/async.c (DEBUG_LINE): New macro.
> > > * io/async.h (RWLOCK_DEBUG_ADD): New macro.
> > > (CHECK_RDLOCK): New macro.
> > > (CHECK_WRLOCK): New macro.
> > > (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
> > > (IN_RWLOCK_DEBUG_QUEUE): New macro.
> > > (RDLOCK): New macro.
> > > (WRLOCK): New macro.
> > > (RWUNLOCK): New macro.
> > > (RD_TO_WRLOCK): New macro.
> > > (INTERN_RDLOCK): New macro.
> > > (INTERN_WRLOCK): New macro.
> > > (INTERN_RWUNLOCK): New macro.
> > > * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
> > > a comment.
> > > (unit_lock): Remove including associated internal_proto.
> > > (unit_rwlock): New declarations including associated internal_proto.
> > > (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
> > > instead of __gthread_mutex_lock and __gthread_mutex_unlock on
> > > unit_lock.
> > > * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK
> > on
> > > unit_rwlock instead of LOCK and UNLOCK on unit_lock.
> > > (st_write_done_worker): Likewise.
> > > * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
> > > comment. Use unit_rwlock variable instead of unit_lock variable.
> > > (get_gfc_unit_from_unit_root): New function.
> > > (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
> > > instead of LOCK and UNLOCK on unit_lock.
> > > (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> > of
> > > LOCK and UNLOCK on unit_lock.
> > > (close_units): Likewise.
> > > (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
> > > unit_lock.
> > > * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
> > > instead of LOCK and UNLOCK on unit_lock.
> > > (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> > > of LOCK and UNLOCK on unit_lock.
> >
> > Ok for trunk, thanks.
> >
> > Jakub
>
> Thanks! Looking forward to landing to trunk.
>
> Lipeng Zhu
Pushed for you.
Thanks.
On 2023/12/12 1:45, H.J. Lu wrote:
> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
> >
> > On 2023/12/9 23:23, Jakub Jelinek wrote:
> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
> > > > This patch try to introduce the rwlock and split the read/write to
> > > > unit_root tree and unit_cache with rwlock instead of the mutex to
> > > > increase CPU efficiency. In the get_gfc_unit function, the
> > > > percentage to step into the insert_unit function is around 30%, in
> > > > most instances, we can get the unit in the phase of reading the
> > > > unit_cache or unit_root tree. So split the read/write phase by
> > > > rwlock would be an approach to make it more parallel.
> > > >
> > > > BTW, the IPC metrics can gain around 9x in our test server with
> > > > 220 cores. The benchmark we used is
> > > > https://github.com/rwesson/NEAT
> > > >
> > > > libgcc/ChangeLog:
> > > >
> > > > * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
> > > > (__gthrw): New function.
> > > > (__gthread_rwlock_rdlock): New function.
> > > > (__gthread_rwlock_tryrdlock): New function.
> > > > (__gthread_rwlock_wrlock): New function.
> > > > (__gthread_rwlock_trywrlock): New function.
> > > > (__gthread_rwlock_unlock): New function.
> > > >
> > > > libgfortran/ChangeLog:
> > > >
> > > > * io/async.c (DEBUG_LINE): New macro.
> > > > * io/async.h (RWLOCK_DEBUG_ADD): New macro.
> > > > (CHECK_RDLOCK): New macro.
> > > > (CHECK_WRLOCK): New macro.
> > > > (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
> > > > (IN_RWLOCK_DEBUG_QUEUE): New macro.
> > > > (RDLOCK): New macro.
> > > > (WRLOCK): New macro.
> > > > (RWUNLOCK): New macro.
> > > > (RD_TO_WRLOCK): New macro.
> > > > (INTERN_RDLOCK): New macro.
> > > > (INTERN_WRLOCK): New macro.
> > > > (INTERN_RWUNLOCK): New macro.
> > > > * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
> > > > a comment.
> > > > (unit_lock): Remove including associated internal_proto.
> > > > (unit_rwlock): New declarations including associated internal_proto.
> > > > (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on
> unit_rwlock
> > > > instead of __gthread_mutex_lock and __gthread_mutex_unlock on
> > > > unit_lock.
> > > > * io/transfer.c (st_read_done_worker): Use WRLOCK and
> RWUNLOCK
> > > on
> > > > unit_rwlock instead of LOCK and UNLOCK on unit_lock.
> > > > (st_write_done_worker): Likewise.
> > > > * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
> > > > comment. Use unit_rwlock variable instead of unit_lock variable.
> > > > (get_gfc_unit_from_unit_root): New function.
> > > > (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on
> unit_rwlock
> > > > instead of LOCK and UNLOCK on unit_lock.
> > > > (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> > > of
> > > > LOCK and UNLOCK on unit_lock.
> > > > (close_units): Likewise.
> > > > (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK
> on
> > > > unit_lock.
> > > > * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
> > > > instead of LOCK and UNLOCK on unit_lock.
> > > > (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock
> instead
> > > > of LOCK and UNLOCK on unit_lock.
> > >
> > > Ok for trunk, thanks.
> > >
> > > Jakub
> >
> > Thanks! Looking forward to landing to trunk.
> >
> > Lipeng Zhu
>
> Pushed for you.
>
> Thanks.
>
> --
> H.J.
Thanks for everyone's patience and help, really appreciate that!
Lipeng Zhu
Hi Lipeng!
On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
> On 2023/12/12 1:45, H.J. Lu wrote:
>> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
>> > On 2023/12/9 23:23, Jakub Jelinek wrote:
>> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>> > > > This patch try to introduce the rwlock and split the read/write to
>> > > > unit_root tree and unit_cache with rwlock instead of the mutex to
>> > > > increase CPU efficiency. In the get_gfc_unit function, the
>> > > > percentage to step into the insert_unit function is around 30%, in
>> > > > most instances, we can get the unit in the phase of reading the
>> > > > unit_cache or unit_root tree. So split the read/write phase by
>> > > > rwlock would be an approach to make it more parallel.
>> > > >
>> > > > BTW, the IPC metrics can gain around 9x in our test server with
>> > > > 220 cores. The benchmark we used is
>> > > > https://github.com/rwesson/NEAT
>> > > Ok for trunk, thanks.
>> > Thanks! Looking forward to landing to trunk.
>> Pushed for you.
> Thanks for everyone's patience and help, really appreciate that!
Congratulations on your first contribution to GCC (as far as I can tell)!
:-)
I've just filed <https://gcc.gnu.org/PR113005>
"'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution test timeouts".
Would you be able to look into that?
Grüße
Thomas
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
On 2023/12/14 4:52, Thomas Schwinge wrote:
> Hi Lipeng!
>
> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
> > On 2023/12/12 1:45, H.J. Lu wrote:
> >> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com>
> wrote:
> >> > On 2023/12/9 23:23, Jakub Jelinek wrote:
> >> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
> >> > > > This patch try to introduce the rwlock and split the read/write
> >> > > > to unit_root tree and unit_cache with rwlock instead of the
> >> > > > mutex to increase CPU efficiency. In the get_gfc_unit function,
> >> > > > the percentage to step into the insert_unit function is around
> >> > > > 30%, in most instances, we can get the unit in the phase of
> >> > > > reading the unit_cache or unit_root tree. So split the
> >> > > > read/write phase by rwlock would be an approach to make it more
> parallel.
> >> > > >
> >> > > > BTW, the IPC metrics can gain around 9x in our test server with
> >> > > > 220 cores. The benchmark we used is
> >> > > > https://github.com/rwesson/NEAT
>
> >> > > Ok for trunk, thanks.
>
> >> > Thanks! Looking forward to landing to trunk.
>
> >> Pushed for you.
>
> > Thanks for everyone's patience and help, really appreciate that!
>
> Congratulations on your first contribution to GCC (as far as I can tell)!
> :-)
>
>
> I've just filed <https://gcc.gnu.org/PR113005>
> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution
> test timeouts".
> Would you be able to look into that?
>
>
> Grüße
> Thomas
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201,
> 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer:
> Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München;
> Registergericht München, HRB 106955
Hi Thomas,
Sure, I will look into that.
BTW, I didn’t have the PowerPC in hands, do you mind granting the access of your
test environment to me to help reproduce the issue?
Lipeng Zhu
Hi Lipeng!
On 2023-12-14T02:28:22+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
> On 2023/12/14 4:52, Thomas Schwinge wrote:
>> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>> > On 2023/12/12 1:45, H.J. Lu wrote:
>> >> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com>
>> wrote:
>> >> > On 2023/12/9 23:23, Jakub Jelinek wrote:
>> >> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>> >> > > > This patch try to introduce the rwlock and split the read/write
>> >> > > > to unit_root tree and unit_cache with rwlock instead of the
>> >> > > > mutex to increase CPU efficiency. In the get_gfc_unit function,
>> >> > > > the percentage to step into the insert_unit function is around
>> >> > > > 30%, in most instances, we can get the unit in the phase of
>> >> > > > reading the unit_cache or unit_root tree. So split the
>> >> > > > read/write phase by rwlock would be an approach to make it more
>> parallel.
>> >> > > >
>> >> > > > BTW, the IPC metrics can gain around 9x in our test server with
>> >> > > > 220 cores. The benchmark we used is
>> >> > > > https://github.com/rwesson/NEAT
>> I've just filed <https://gcc.gnu.org/PR113005>
>> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution
>> test timeouts".
>> Would you be able to look into that?
> Sure, I will look into that.
>
> BTW, I didn’t have the PowerPC in hands, do you mind granting the access of your
> test environment to me to help reproduce the issue?
That's unfortunately not possible: it's behind company VPN, restricted
access. :-/ I'll later try to have at least a quick look where it's
hanging, or what it's doing.
Grüße
Thomas
-----------------
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On Thu, Dec 14, 2023 at 01:29:01PM +0100, Thomas Schwinge wrote:
> > Sure, I will look into that.
> >
> > BTW, I didn’t have the PowerPC in hands, do you mind granting the access of your
> > test environment to me to help reproduce the issue?
>
> That's unfortunately not possible: it's behind company VPN, restricted
> access. :-/ I'll later try to have at least a quick look where it's
> hanging, or what it's doing.
There is always https://gcc.gnu.org/wiki/CompileFarm
There are e.g. 192, 160, 128, 80, 64 thread power machines.
Whether any of them can actually reproduce it, I haven't tried.
But shouldn't be that time consuming to reproduce, for this kind of thing
one can just build
.../configure --enable-languages=c,c++,fortran --disable-bootstrap --disable-libsanitizer
make -jN
compiler and just
cd power*/libgomp
make check RUNTESTFLAGS=fortran.exp=rwlock*.f90
repeatedly to see if it gets stuck.
Jakub
On 09/12/2023 15:39, Lipeng Zhu wrote:
> This patch try to introduce the rwlock and split the read/write to
> unit_root tree and unit_cache with rwlock instead of the mutex to
> increase CPU efficiency. In the get_gfc_unit function, the percentage
> to step into the insert_unit function is around 30%, in most instances,
> we can get the unit in the phase of reading the unit_cache or unit_root
> tree. So split the read/write phase by rwlock would be an approach to
> make it more parallel.
>
> BTW, the IPC metrics can gain around 9x in our test
> server with 220 cores. The benchmark we used is
> https://github.com/rwesson/NEAT
>
> libgcc/ChangeLog:
>
> * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
> (__gthrw): New function.
> (__gthread_rwlock_rdlock): New function.
> (__gthread_rwlock_tryrdlock): New function.
> (__gthread_rwlock_wrlock): New function.
> (__gthread_rwlock_trywrlock): New function.
> (__gthread_rwlock_unlock): New function.
>
> libgfortran/ChangeLog:
>
> * io/async.c (DEBUG_LINE): New macro.
> * io/async.h (RWLOCK_DEBUG_ADD): New macro.
> (CHECK_RDLOCK): New macro.
> (CHECK_WRLOCK): New macro.
> (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
> (IN_RWLOCK_DEBUG_QUEUE): New macro.
> (RDLOCK): New macro.
> (WRLOCK): New macro.
> (RWUNLOCK): New macro.
> (RD_TO_WRLOCK): New macro.
> (INTERN_RDLOCK): New macro.
> (INTERN_WRLOCK): New macro.
> (INTERN_RWUNLOCK): New macro.
> * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
> a comment.
> (unit_lock): Remove including associated internal_proto.
> (unit_rwlock): New declarations including associated internal_proto.
> (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
> instead of __gthread_mutex_lock and __gthread_mutex_unlock on
> unit_lock.
> * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
> unit_rwlock instead of LOCK and UNLOCK on unit_lock.
> (st_write_done_worker): Likewise.
> * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
> comment. Use unit_rwlock variable instead of unit_lock variable.
> (get_gfc_unit_from_unit_root): New function.
> (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
> instead of LOCK and UNLOCK on unit_lock.
> (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
> LOCK and UNLOCK on unit_lock.
> (close_units): Likewise.
> (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
> unit_lock.
> * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
> instead of LOCK and UNLOCK on unit_lock.
> (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
> of LOCK and UNLOCK on unit_lock.
>
It looks like this has broken builds on arm-none-eabi when using newlib:
In file included from /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran
/runtime/error.c:27:
/work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h: In function
‘dec_waiting_unlocked’:
/work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1023:3: error
: implicit declaration of function ‘WRLOCK’ [-Wimplicit-function-declaration]
1023 | WRLOCK (&unit_rwlock);
| ^~~~~~
/work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1025:3: error
: implicit declaration of function ‘RWUNLOCK’ [-Wimplicit-function-declaration]
1025 | RWUNLOCK (&unit_rwlock);
| ^~~~~~~~
R.
> ---
> v1 -> v2:
> Limit the pthread_rwlock usage in libgcc only when __cplusplus isn't defined.
>
> v2 -> v3:
> Rebase the patch with trunk branch.
>
> v3 -> v4:
> Update the comments.
>
> v4 -> v5:
> Fix typos and code formatter.
>
> v5 -> v6:
> Add unit tests.
>
> v6 -> v7:
> Update ChangeLog and code formatter.
>
> Reviewed-by: Hongjiu Lu <hongjiu.lu@intel.com>
> Reviewed-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
> Reviewed-by: Thomas Koenig <tkoenig@netcologne.de>
> Reviewed-by: Jakub Jelinek <jakub@redhat.com>
> Signed-off-by: Lipeng Zhu <lipeng.zhu@intel.com>
> ---
> libgcc/gthr-posix.h | 60 +++++++
> libgfortran/io/async.c | 4 +
> libgfortran/io/async.h | 151 ++++++++++++++++++
> libgfortran/io/io.h | 15 +-
> libgfortran/io/transfer.c | 8 +-
> libgfortran/io/unit.c | 117 +++++++++-----
> libgfortran/io/unix.c | 16 +-
> .../testsuite/libgomp.fortran/rwlock_1.f90 | 33 ++++
> .../testsuite/libgomp.fortran/rwlock_2.f90 | 22 +++
> .../testsuite/libgomp.fortran/rwlock_3.f90 | 18 +++
> 10 files changed, 386 insertions(+), 58 deletions(-)
> create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_1.f90
> create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_2.f90
> create mode 100644 libgomp/testsuite/libgomp.fortran/rwlock_3.f90
>
> diff --git a/libgcc/gthr-posix.h b/libgcc/gthr-posix.h
> index aebcfdd9f4c..73283082997 100644
> --- a/libgcc/gthr-posix.h
> +++ b/libgcc/gthr-posix.h
> @@ -48,6 +48,9 @@ typedef pthread_t __gthread_t;
> typedef pthread_key_t __gthread_key_t;
> typedef pthread_once_t __gthread_once_t;
> typedef pthread_mutex_t __gthread_mutex_t;
> +#ifndef __cplusplus
> +typedef pthread_rwlock_t __gthread_rwlock_t;
> +#endif
> typedef pthread_mutex_t __gthread_recursive_mutex_t;
> typedef pthread_cond_t __gthread_cond_t;
> typedef struct timespec __gthread_time_t;
> @@ -58,6 +61,9 @@ typedef struct timespec __gthread_time_t;
>
> #define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
> #define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
> +#ifndef __cplusplus
> +#define __GTHREAD_RWLOCK_INIT PTHREAD_RWLOCK_INITIALIZER
> +#endif
> #define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
> #if defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
> #define __GTHREAD_RECURSIVE_MUTEX_INIT PTHREAD_RECURSIVE_MUTEX_INITIALIZER
> @@ -135,6 +141,13 @@ __gthrw(pthread_mutexattr_init)
> __gthrw(pthread_mutexattr_settype)
> __gthrw(pthread_mutexattr_destroy)
>
> +#ifndef __cplusplus
> +__gthrw(pthread_rwlock_rdlock)
> +__gthrw(pthread_rwlock_tryrdlock)
> +__gthrw(pthread_rwlock_wrlock)
> +__gthrw(pthread_rwlock_trywrlock)
> +__gthrw(pthread_rwlock_unlock)
> +#endif
>
> #if defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)
> /* Objective-C. */
> @@ -885,6 +898,53 @@ __gthread_cond_destroy (__gthread_cond_t* __cond)
> return __gthrw_(pthread_cond_destroy) (__cond);
> }
>
> +#ifndef __cplusplus
> +static inline int
> +__gthread_rwlock_rdlock (__gthread_rwlock_t *__rwlock)
> +{
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_rwlock_rdlock) (__rwlock);
> + else
> + return 0;
> +}
> +
> +static inline int
> +__gthread_rwlock_tryrdlock (__gthread_rwlock_t *__rwlock)
> +{
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_rwlock_tryrdlock) (__rwlock);
> + else
> + return 0;
> +}
> +
> +static inline int
> +__gthread_rwlock_wrlock (__gthread_rwlock_t *__rwlock)
> +{
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_rwlock_wrlock) (__rwlock);
> + else
> + return 0;
> +}
> +
> +static inline int
> +__gthread_rwlock_trywrlock (__gthread_rwlock_t *__rwlock)
> +{
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_rwlock_trywrlock) (__rwlock);
> + else
> + return 0;
> +}
> +
> +static inline int
> +__gthread_rwlock_unlock (__gthread_rwlock_t *__rwlock)
> +{
> + if (__gthread_active_p ())
> + return __gthrw_(pthread_rwlock_unlock) (__rwlock);
> + else
> + return 0;
> +}
> +#endif
> +
> #endif /* _LIBOBJC */
>
> #endif /* ! GCC_GTHR_POSIX_H */
> diff --git a/libgfortran/io/async.c b/libgfortran/io/async.c
> index 8fa1f0d4ce0..91bf397105d 100644
> --- a/libgfortran/io/async.c
> +++ b/libgfortran/io/async.c
> @@ -42,6 +42,10 @@ DEBUG_LINE (__thread const char *aio_prefix = MPREFIX);
>
> DEBUG_LINE (__gthread_mutex_t debug_queue_lock = __GTHREAD_MUTEX_INIT;)
> DEBUG_LINE (aio_lock_debug *aio_debug_head = NULL;)
> +#ifdef __GTHREAD_RWLOCK_INIT
> +DEBUG_LINE (aio_rwlock_debug *aio_rwlock_debug_head = NULL;)
> +DEBUG_LINE (__gthread_rwlock_t debug_queue_rwlock = __GTHREAD_RWLOCK_INIT;)
> +#endif
>
> /* Current unit for asynchronous I/O. Needed for error reporting. */
>
> diff --git a/libgfortran/io/async.h b/libgfortran/io/async.h
> index ad226c8e856..f112f6870bb 100644
> --- a/libgfortran/io/async.h
> +++ b/libgfortran/io/async.h
> @@ -210,6 +210,128 @@
> DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #mutex, mutex); \
> } while (0)
>
> +#ifdef __GTHREAD_RWLOCK_INIT
> +#define RWLOCK_DEBUG_ADD(rwlock) do { \
> + aio_rwlock_debug *n; \
> + n = xmalloc (sizeof (aio_rwlock_debug)); \
> + n->prev = TAIL_RWLOCK_DEBUG_QUEUE; \
> + if (n->prev) \
> + n->prev->next = n; \
> + n->next = NULL; \
> + n->line = __LINE__; \
> + n->func = __FUNCTION__; \
> + n->rw = rwlock; \
> + if (!aio_rwlock_debug_head) { \
> + aio_rwlock_debug_head = n; \
> + } \
> + } while (0)
> +
> +#define CHECK_RDLOCK(rwlock, status) do { \
> + aio_rwlock_debug *curr; \
> + INTERN_WRLOCK (&debug_queue_rwlock); \
> + if (__gthread_rwlock_tryrdlock (rwlock)) { \
> + if ((curr = IN_RWLOCK_DEBUG_QUEUE (rwlock))) { \
> + sprintf (status, DEBUG_RED "%s():%d" DEBUG_NORM, curr->func, curr->line); \
> + } else \
> + sprintf (status, DEBUG_RED "unknown" DEBUG_NORM); \
> + } \
> + else { \
> + __gthread_rwlock_unlock (rwlock); \
> + sprintf (status, DEBUG_GREEN "rwunlocked" DEBUG_NORM); \
> + } \
> + INTERN_RWUNLOCK (&debug_queue_rwlock); \
> + }while (0)
> +
> +#define CHECK_WRLOCK(rwlock, status) do { \
> + aio_rwlock_debug *curr; \
> + INTERN_WRLOCK (&debug_queue_rwlock); \
> + if (__gthread_rwlock_trywrlock (rwlock)) { \
> + if ((curr = IN_RWLOCK_DEBUG_QUEUE (rwlock))) { \
> + sprintf (status, DEBUG_RED "%s():%d" DEBUG_NORM, curr->func, curr->line); \
> + } else \
> + sprintf (status, DEBUG_RED "unknown" DEBUG_NORM); \
> + } \
> + else { \
> + __gthread_rwlock_unlock (rwlock); \
> + sprintf (status, DEBUG_GREEN "rwunlocked" DEBUG_NORM); \
> + } \
> + INTERN_RWUNLOCK (&debug_queue_rwlock); \
> + }while (0)
> +
> +#define TAIL_RWLOCK_DEBUG_QUEUE ({ \
> + aio_rwlock_debug *curr = aio_rwlock_debug_head; \
> + while (curr && curr->next) { \
> + curr = curr->next; \
> + } \
> + curr; \
> + })
> +
> +#define IN_RWLOCK_DEBUG_QUEUE(rwlock) ({ \
> + __label__ end; \
> + aio_rwlock_debug *curr = aio_rwlock_debug_head; \
> + while (curr) { \
> + if (curr->rw == rwlock) { \
> + goto end; \
> + } \
> + curr = curr->next; \
> + } \
> + end:; \
> + curr; \
> + })
> +
> +#define RDLOCK(rwlock) do { \
> + char status[200]; \
> + CHECK_RDLOCK (rwlock, status); \
> + DEBUG_PRINTF ("%s%-42s prev: %-35s %20s():%-5d %18p\n", aio_prefix, \
> + DEBUG_RED "RDLOCK: " DEBUG_NORM #rwlock, status, __FUNCTION__, __LINE__, (void *) rwlock); \
> + INTERN_RDLOCK (rwlock); \
> + INTERN_WRLOCK (&debug_queue_rwlock); \
> + RWLOCK_DEBUG_ADD (rwlock); \
> + INTERN_RWUNLOCK (&debug_queue_rwlock); \
> + DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #rwlock, rwlock); \
> + } while (0)
> +
> +#define WRLOCK(rwlock) do { \
> + char status[200]; \
> + CHECK_WRLOCK (rwlock, status); \
> + DEBUG_PRINTF ("%s%-42s prev: %-35s %20s():%-5d %18p\n", aio_prefix, \
> + DEBUG_RED "WRLOCK: " DEBUG_NORM #rwlock, status, __FUNCTION__, __LINE__, (void *) rwlock); \
> + INTERN_WRLOCK (rwlock); \
> + INTERN_WRLOCK (&debug_queue_rwlock); \
> + RWLOCK_DEBUG_ADD (rwlock); \
> + INTERN_RWUNLOCK (&debug_queue_rwlock); \
> + DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #rwlock, rwlock); \
> + } while (0)
> +
> +#define RWUNLOCK(rwlock) do { \
> + aio_rwlock_debug *curr; \
> + DEBUG_PRINTF ("%s%-75s %20s():%-5d %18p\n", aio_prefix, DEBUG_GREEN "RWUNLOCK: " DEBUG_NORM #rwlock, \
> + __FUNCTION__, __LINE__, (void *) rwlock); \
> + INTERN_WRLOCK (&debug_queue_rwlock); \
> + curr = IN_RWLOCK_DEBUG_QUEUE (rwlock); \
> + if (curr) \
> + { \
> + if (curr->prev) \
> + curr->prev->next = curr->next; \
> + if (curr->next) { \
> + curr->next->prev = curr->prev; \
> + if (curr == aio_rwlock_debug_head) \
> + aio_rwlock_debug_head = curr->next; \
> + } else { \
> + if (curr == aio_rwlock_debug_head) \
> + aio_rwlock_debug_head = NULL; \
> + } \
> + free (curr); \
> + } \
> + INTERN_RWUNLOCK (&debug_queue_rwlock); \
> + INTERN_RWUNLOCK (rwlock); \
> + } while (0)
> +
> +#define RD_TO_WRLOCK(rwlock) \
> + RWUNLOCK (rwlock); \
> + WRLOCK (rwlock);
> +#endif
> +
> #define DEBUG_LINE(...) __VA_ARGS__
>
> #else
> @@ -221,12 +343,31 @@
> #define LOCK(mutex) INTERN_LOCK (mutex)
> #define UNLOCK(mutex) INTERN_UNLOCK (mutex)
> #define TRYLOCK(mutex) (__gthread_mutex_trylock (mutex))
> +#ifdef __GTHREAD_RWLOCK_INIT
> +#define RDLOCK(rwlock) INTERN_RDLOCK (rwlock)
> +#define WRLOCK(rwlock) INTERN_WRLOCK (rwlock)
> +#define RWUNLOCK(rwlock) INTERN_RWUNLOCK (rwlock)
> +#define RD_TO_WRLOCK(rwlock) \
> + RWUNLOCK (rwlock); \
> + WRLOCK (rwlock);
> +#endif
> +#endif
> +
> +#ifndef __GTHREAD_RWLOCK_INIT
> +#define RDLOCK(rwlock) LOCK (rwlock)
> +#define WRLOCK(rwlock) LOCK (rwlock)
> +#define RWUNLOCK(rwlock) UNLOCK (rwlock)
> +#define RD_TO_WRLOCK(rwlock) do {} while (0)
> #endif
>
> #define INTERN_LOCK(mutex) T_ERROR (__gthread_mutex_lock, mutex);
>
> #define INTERN_UNLOCK(mutex) T_ERROR (__gthread_mutex_unlock, mutex);
>
> +#define INTERN_RDLOCK(rwlock) T_ERROR (__gthread_rwlock_rdlock, rwlock)
> +#define INTERN_WRLOCK(rwlock) T_ERROR (__gthread_rwlock_wrlock, rwlock)
> +#define INTERN_RWUNLOCK(rwlock) T_ERROR (__gthread_rwlock_unlock, rwlock)
> +
> #if ASYNC_IO
>
> /* au->lock has to be held when calling this macro. */
> @@ -288,8 +429,18 @@ DEBUG_LINE (typedef struct aio_lock_debug{
> struct aio_lock_debug *prev;
> } aio_lock_debug;)
>
> +DEBUG_LINE (typedef struct aio_rwlock_debug{
> + __gthread_rwlock_t *rw;
> + int line;
> + const char *func;
> + struct aio_rwlock_debug *next;
> + struct aio_rwlock_debug *prev;
> +} aio_rwlock_debug;)
> +
> DEBUG_LINE (extern aio_lock_debug *aio_debug_head;)
> DEBUG_LINE (extern __gthread_mutex_t debug_queue_lock;)
> +DEBUG_LINE (extern aio_rwlock_debug *aio_rwlock_debug_head;)
> +DEBUG_LINE (extern __gthread_rwlock_t debug_queue_rwlock;)
>
> /* Thread - local storage of the current unit we are looking at. Needed for
> error reporting. */
> diff --git a/libgfortran/io/io.h b/libgfortran/io/io.h
> index ecdf1dd3f05..15daa0995b1 100644
> --- a/libgfortran/io/io.h
> +++ b/libgfortran/io/io.h
> @@ -690,7 +690,7 @@ typedef struct gfc_unit
> from the UNIT_ROOT tree, but doesn't free it and the
> last of the waiting threads will do that.
> This must be either atomically increased/decreased, or
> - always guarded by UNIT_LOCK. */
> + always guarded by UNIT_RWLOCK. */
> int waiting;
> /* Flag set by close_unit if the unit as been closed.
> Must be manipulated under unit's lock. */
> @@ -769,8 +769,13 @@ internal_proto(default_recl);
> extern gfc_unit *unit_root;
> internal_proto(unit_root);
>
> -extern __gthread_mutex_t unit_lock;
> -internal_proto(unit_lock);
> +#ifdef __GTHREAD_RWLOCK_INIT
> +extern __gthread_rwlock_t unit_rwlock;
> +internal_proto(unit_rwlock);
> +#else
> +extern __gthread_mutex_t unit_rwlock;
> +internal_proto(unit_rwlock);
> +#endif
>
> extern int close_unit (gfc_unit *);
> internal_proto(close_unit);
> @@ -1015,9 +1020,9 @@ dec_waiting_unlocked (gfc_unit *u)
> #ifdef HAVE_ATOMIC_FETCH_ADD
> (void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
> #else
> - __gthread_mutex_lock (&unit_lock);
> + WRLOCK (&unit_rwlock);
> u->waiting--;
> - __gthread_mutex_unlock (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> #endif
> }
>
> diff --git a/libgfortran/io/transfer.c b/libgfortran/io/transfer.c
> index 500db90c828..00d516adcb0 100644
> --- a/libgfortran/io/transfer.c
> +++ b/libgfortran/io/transfer.c
> @@ -4538,9 +4538,9 @@ st_read_done_worker (st_parameter_dt *dtp, bool unlock)
> if (free_newunit)
> {
> /* Avoid inverse lock issues by placing after unlock_unit. */
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> newunit_free (dtp->common.unit);
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> }
> }
>
> @@ -4634,9 +4634,9 @@ st_write_done_worker (st_parameter_dt *dtp, bool unlock)
> if (free_newunit)
> {
> /* Avoid inverse lock issues by placing after unlock_unit. */
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> newunit_free (dtp->common.unit);
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> }
> }
>
> diff --git a/libgfortran/io/unit.c b/libgfortran/io/unit.c
> index 36d025949c2..0c8c35e464e 100644
> --- a/libgfortran/io/unit.c
> +++ b/libgfortran/io/unit.c
> @@ -33,34 +33,36 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
>
>
> /* IO locking rules:
> - UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
> + UNIT_RWLOCK is a master rw lock, protecting UNIT_ROOT tree and UNIT_CACHE.
> + Using an rwlock improves efficiency by allowing us to separate readers
> + and writers of both UNIT_ROOT and UNIT_CACHE.
> Concurrent use of different units should be supported, so
> each unit has its own lock, LOCK.
> Open should be atomic with its reopening of units and list_read.c
> in several places needs find_unit another unit while holding stdin
> - unit's lock, so it must be possible to acquire UNIT_LOCK while holding
> + unit's lock, so it must be possible to acquire UNIT_RWLOCK while holding
> some unit's lock. Therefore to avoid deadlocks, it is forbidden
> - to acquire unit's private locks while holding UNIT_LOCK, except
> + to acquire unit's private locks while holding UNIT_RWLOCK, except
> for freshly created units (where no other thread can get at their
> address yet) or when using just trylock rather than lock operation.
> In addition to unit's private lock each unit has a WAITERS counter
> and CLOSED flag. WAITERS counter must be either only
> atomically incremented/decremented in all places (if atomic builtins
> - are supported), or protected by UNIT_LOCK in all places (otherwise).
> + are supported), or protected by UNIT_RWLOCK in all places (otherwise).
> CLOSED flag must be always protected by unit's LOCK.
> - After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
> + After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_RWLOCK held,
> WAITERS must be incremented to avoid concurrent close from freeing
> - the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
> - Unit freeing is always done under UNIT_LOCK. If close_unit sees any
> + the unit between unlocking UNIT_RWLOCK and acquiring unit's LOCK.
> + Unit freeing is always done under UNIT_RWLOCK. If close_unit sees any
> WAITERS, it doesn't free the unit but instead sets the CLOSED flag
> and the thread that decrements WAITERS to zero while CLOSED flag is
> - set is responsible for freeing it (while holding UNIT_LOCK).
> + set is responsible for freeing it (while holding UNIT_RWLOCK).
> flush_all_units operation is iterating over the unit tree with
> - increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
> + increasing UNIT_NUMBER while holding UNIT_RWLOCK and attempting to
> flush each unit (and therefore needs the unit's LOCK held as well).
> To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
> - remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
> - unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
> + remembers the current unit's UNIT_NUMBER, unlocks UNIT_RWLOCK, acquires
> + unit's LOCK and after flushing reacquires UNIT_RWLOCK and restarts with
> the smallest UNIT_NUMBER above the last one flushed.
>
> If find_unit/find_or_create_unit/find_file/get_unit routines return
> @@ -101,10 +103,14 @@ gfc_offset max_offset;
> gfc_offset default_recl;
>
> gfc_unit *unit_root;
> +#ifdef __GTHREAD_RWLOCK_INIT
> +__gthread_rwlock_t unit_rwlock = __GTHREAD_RWLOCK_INIT;
> +#else
> #ifdef __GTHREAD_MUTEX_INIT
> -__gthread_mutex_t unit_lock = __GTHREAD_MUTEX_INIT;
> +__gthread_mutex_t unit_rwlock = __GTHREAD_MUTEX_INIT;
> #else
> -__gthread_mutex_t unit_lock;
> +__gthread_mutex_t unit_rwlock;
> +#endif
> #endif
>
> /* We use these filenames for error reporting. */
> @@ -317,6 +323,28 @@ delete_unit (gfc_unit *old)
> unit_root = delete_treap (old, unit_root);
> }
>
> +/* get_gfc_unit_from_root()-- Given an integer, return a pointer
> + to the unit structure. Returns NULL if the unit does not exist,
> + otherwise returns a locked unit. */
> +
> +static inline gfc_unit *
> +get_gfc_unit_from_unit_root (int n)
> +{
> + gfc_unit *p;
> + int c = 0;
> + p = unit_root;
> + while (p != NULL)
> + {
> + c = compare (n, p->unit_number);
> + if (c < 0)
> + p = p->left;
> + if (c > 0)
> + p = p->right;
> + if (c == 0)
> + break;
> + }
> + return p;
> +}
>
> /* get_gfc_unit()-- Given an integer, return a pointer to the unit
> structure. Returns NULL if the unit does not exist,
> @@ -329,7 +357,7 @@ get_gfc_unit (int n, int do_create)
> int c, created = 0;
>
> NOTE ("Unit n=%d, do_create = %d", n, do_create);
> - LOCK (&unit_lock);
> + RDLOCK (&unit_rwlock);
>
> retry:
> for (c = 0; c < CACHE_SIZE; c++)
> @@ -339,18 +367,25 @@ retry:
> goto found;
> }
>
> - p = unit_root;
> - while (p != NULL)
> - {
> - c = compare (n, p->unit_number);
> - if (c < 0)
> - p = p->left;
> - if (c > 0)
> - p = p->right;
> - if (c == 0)
> - break;
> - }
> -
> + p = get_gfc_unit_from_unit_root (n);
> +
> + /* We did not find a unit in the cache nor in the unit list,
> + create a new (locked) unit and insert into the unit list and
> + cache. Manipulating either or both the unit list and the unit
> + cache requires to hold a write-lock [for obvious reasons]:
> + By separating the read/write lock, we will greatly reduce
> + the contention on the read part, while the write part is
> + unlikely once the unit hits the cache. */
> + RD_TO_WRLOCK (&unit_rwlock);
> +
> + /* In the case of high concurrency, when multiple threads want
> + to find or create the same unit, the unit number may not
> + exist in cache nor in the unit list during read phase, then
> + threads will acquire the write-lock to insert the same unit
> + number to unit list. To avoid duplicate insert, we need to
> + find unit list once again to ensure that the unit number
> + not exist. */
> + p = get_gfc_unit_from_unit_root (n);
> if (p == NULL && do_create)
> {
> p = insert_unit (n);
> @@ -368,8 +403,8 @@ retry:
> if (created)
> {
> /* Newly created units have their lock held already
> - from insert_unit. Just unlock UNIT_LOCK and return. */
> - UNLOCK (&unit_lock);
> + from insert_unit. Just unlock UNIT_RWLOCK and return. */
> + RWUNLOCK (&unit_rwlock);
> return p;
> }
>
> @@ -380,7 +415,7 @@ found:
> if (! TRYLOCK (&p->lock))
> {
> /* assert (p->closed == 0); */
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> return p;
> }
>
> @@ -388,14 +423,14 @@ found:
> }
>
>
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
>
> if (p != NULL && (p->child_dtio == 0))
> {
> LOCK (&p->lock);
> if (p->closed)
> {
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> UNLOCK (&p->lock);
> if (predec_waiting_locked (p) == 0)
> destroy_unit_mutex (p);
> @@ -594,8 +629,8 @@ init_units (void)
> #endif
> #endif
>
> -#ifndef __GTHREAD_MUTEX_INIT
> - __GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock);
> +#if (!defined(__GTHREAD_RWLOCK_INIT) && !defined(__GTHREAD_MUTEX_INIT))
> + __GTHREAD_MUTEX_INIT_FUNCTION (&unit_rwlock);
> #endif
>
> if (sizeof (max_offset) == 8)
> @@ -732,7 +767,7 @@ close_unit_1 (gfc_unit *u, int locked)
>
> u->closed = 1;
> if (!locked)
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
>
> for (i = 0; i < CACHE_SIZE; i++)
> if (unit_cache[i] == u)
> @@ -759,7 +794,7 @@ close_unit_1 (gfc_unit *u, int locked)
> destroy_unit_mutex (u);
>
> if (!locked)
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
>
> return rc;
> }
> @@ -796,10 +831,10 @@ close_unit (gfc_unit *u)
> void
> close_units (void)
> {
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> while (unit_root != NULL)
> close_unit_1 (unit_root, 1);
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
>
> free (newunits);
>
> @@ -906,7 +941,7 @@ finish_last_advance_record (gfc_unit *u)
> int
> newunit_alloc (void)
> {
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> if (!newunits)
> {
> newunits = xcalloc (16, 1);
> @@ -920,7 +955,7 @@ newunit_alloc (void)
> {
> newunits[ii] = true;
> newunit_lwi = ii + 1;
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> return -ii + NEWUNIT_START;
> }
> }
> @@ -933,12 +968,12 @@ newunit_alloc (void)
> memset (newunits + old_size, 0, old_size);
> newunits[old_size] = true;
> newunit_lwi = old_size + 1;
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> return -old_size + NEWUNIT_START;
> }
>
>
> -/* Free a previously allocated newunit= unit number. unit_lock must
> +/* Free a previously allocated newunit= unit number. unit_rwlock must
> be held when calling. */
>
> void
> diff --git a/libgfortran/io/unix.c b/libgfortran/io/unix.c
> index d466df979df..dcae051744d 100644
> --- a/libgfortran/io/unix.c
> +++ b/libgfortran/io/unix.c
> @@ -1773,7 +1773,7 @@ find_file (const char *file, gfc_charlen_type file_len)
> id = id_from_path (path);
> #endif
>
> - LOCK (&unit_lock);
> + RDLOCK (&unit_rwlock);
> retry:
> u = find_file0 (unit_root, FIND_FILE0_ARGS);
> if (u != NULL)
> @@ -1782,19 +1782,19 @@ retry:
> if (! __gthread_mutex_trylock (&u->lock))
> {
> /* assert (u->closed == 0); */
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> goto done;
> }
>
> inc_waiting_locked (u);
> }
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> if (u != NULL)
> {
> LOCK (&u->lock);
> if (u->closed)
> {
> - LOCK (&unit_lock);
> + RDLOCK (&unit_rwlock);
> UNLOCK (&u->lock);
> if (predec_waiting_locked (u) == 0)
> free (u);
> @@ -1838,13 +1838,13 @@ flush_all_units (void)
> gfc_unit *u;
> int min_unit = 0;
>
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> do
> {
> u = flush_all_units_1 (unit_root, min_unit);
> if (u != NULL)
> inc_waiting_locked (u);
> - UNLOCK (&unit_lock);
> + RWUNLOCK (&unit_rwlock);
> if (u == NULL)
> return;
>
> @@ -1855,13 +1855,13 @@ flush_all_units (void)
> if (u->closed == 0)
> {
> sflush (u->s);
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> UNLOCK (&u->lock);
> (void) predec_waiting_locked (u);
> }
> else
> {
> - LOCK (&unit_lock);
> + WRLOCK (&unit_rwlock);
> UNLOCK (&u->lock);
> if (predec_waiting_locked (u) == 0)
> free (u);
> diff --git a/libgomp/testsuite/libgomp.fortran/rwlock_1.f90 b/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
> new file mode 100644
> index 00000000000..f90ecbeb00f
> --- /dev/null
> +++ b/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
> @@ -0,0 +1,33 @@
> +! { dg-do run }
> +! Multiple threads call open/write/read/close in concurrency with different unit number,
> +! threads can acquire read lock concurrently, to find unit from cache or unit list very frequently,
> +! if not found, threads will acquire the write lock exclusively to insert unit to cache and unit list.
> +! This test case is used to stress both the read and write lock when access unit cache and list.
> +program main
> + use omp_lib
> + implicit none
> + integer:: unit_number, v1, v2, i
> + character(11) :: file_name
> + character(3) :: async = "no"
> + !$omp parallel private (unit_number, v1, v2, file_name, async, i)
> + do i = 0, 100
> + unit_number = 10 + omp_get_thread_num ()
> + write (file_name, "(I3, A)") unit_number, "_tst.dat"
> + file_name = adjustl(file_name)
> + open (unit_number, file=file_name, asynchronous="yes")
> + ! call inquire with file parameter to test find_file in unix.c
> + inquire (file=file_name, asynchronous=async)
> + if (async /= "YES") stop 1
> + write (unit_number, *, asynchronous="yes") unit_number
> + write (unit_number, *, asynchronous="yes") unit_number + 1
> + close(unit_number)
> +
> + open (unit_number, file = file_name, asynchronous="yes")
> + read (unit_number, *, asynchronous="yes") v1
> + read (unit_number, *, asynchronous="yes") v2
> + wait (unit_number)
> + if ((v1 /= unit_number) .or. (v2 /= unit_number + 1)) stop 2
> + close(unit_number, status="delete")
> + end do
> + !$omp end parallel
> +end program
> diff --git a/libgomp/testsuite/libgomp.fortran/rwlock_2.f90 b/libgomp/testsuite/libgomp.fortran/rwlock_2.f90
> new file mode 100644
> index 00000000000..08c80d14cfb
> --- /dev/null
> +++ b/libgomp/testsuite/libgomp.fortran/rwlock_2.f90
> @@ -0,0 +1,22 @@
> +! { dg-do run }
> +! Insert a unit into cache at the beginning, then start multiple
> +! threads to access the same unit concurrency, unit will be found in unit cache during the read lock phase.
> +! This test case is used to test the read lock when access unit cache and list.
> +program main
> + use omp_lib
> + implicit none
> + integer:: thread_id, total_threads, i, j
> + total_threads = omp_get_max_threads ()
> + open (10, file='tst.dat', asynchronous="yes")
> + !$omp parallel private (thread_id, i, j)
> + do i = 1, 100
> + thread_id = omp_get_thread_num ()
> + do j = 1, 100
> + write (10, *, asynchronous="yes") thread_id, i
> + end do
> + end do
> + !$omp end parallel
> + ! call inquire with file parameter to test find_file in unix.c
> + call flush ()
> + close (10, status="delete")
> +end program
> diff --git a/libgomp/testsuite/libgomp.fortran/rwlock_3.f90 b/libgomp/testsuite/libgomp.fortran/rwlock_3.f90
> new file mode 100644
> index 00000000000..1906fcd7a0b
> --- /dev/null
> +++ b/libgomp/testsuite/libgomp.fortran/rwlock_3.f90
> @@ -0,0 +1,18 @@
> +! { dg-do run }
> +! Find or create the same unit number in concurrency,
> +! at beginning, threads cannot find the unit in cache or unit list,
> +! then threads will acquire the write lock to insert unit.
> +! This test case is used to ensure that no duplicate unit number will be
> +! inserted into cache nor unit list when same unit was accessed in concurrency.
> +program main
> + use omp_lib
> + implicit none
> + integer:: i
> + !$omp parallel private (i)
> + do i = 1, 100
> + open (10, file='tst.dat', asynchronous="yes")
> + ! Delete the unit number from cache and unit list to stress write lock.
> + close (10, status="delete")
> + end do
> + !$omp end parallel
> +end program
On 2023/12/14 20:39, Jakub Jelinek wrote:
> On Thu, Dec 14, 2023 at 01:29:01PM +0100, Thomas Schwinge wrote:
>>> Sure, I will look into that.
>>>
>>> BTW, I didn’t have the PowerPC in hands, do you mind granting the access of your
>>> test environment to me to help reproduce the issue?
>>
>> That's unfortunately not possible: it's behind company VPN, restricted
>> access. :-/ I'll later try to have at least a quick look where it's
>> hanging, or what it's doing.
>
> There is always https://gcc.gnu.org/wiki/CompileFarm
> There are e.g. 192, 160, 128, 80, 64 thread power machines.
Thanks Jakub,
I submit a request to join the CompileFarm project. Could you help to approve it?
Lipeng Zhu
> Whether any of them can actually reproduce it, I haven't tried.
> But shouldn't be that time consuming to reproduce, for this kind of thing
> one can just build
> .../configure --enable-languages=c,c++,fortran --disable-bootstrap --disable-libsanitizer
> make -jN
> compiler and just
> cd power*/libgomp
> make check RUNTESTFLAGS=fortran.exp=rwlock*.f90
> repeatedly to see if it gets stuck.
>
> Jakub
>
>
On 2023/12/14 23:50, Richard Earnshaw (lists) wrote:
> On 09/12/2023 15:39, Lipeng Zhu wrote:
>> This patch try to introduce the rwlock and split the read/write to
>> unit_root tree and unit_cache with rwlock instead of the mutex to
>> increase CPU efficiency. In the get_gfc_unit function, the percentage
>> to step into the insert_unit function is around 30%, in most instances,
>> we can get the unit in the phase of reading the unit_cache or unit_root
>> tree. So split the read/write phase by rwlock would be an approach to
>> make it more parallel.
>>
>> BTW, the IPC metrics can gain around 9x in our test
>> server with 220 cores. The benchmark we used is
>> https://github.com/rwesson/NEAT
>>
>> libgcc/ChangeLog:
>>
>> * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
>> (__gthrw): New function.
>> (__gthread_rwlock_rdlock): New function.
>> (__gthread_rwlock_tryrdlock): New function.
>> (__gthread_rwlock_wrlock): New function.
>> (__gthread_rwlock_trywrlock): New function.
>> (__gthread_rwlock_unlock): New function.
>>
>> libgfortran/ChangeLog:
>>
>> * io/async.c (DEBUG_LINE): New macro.
>> * io/async.h (RWLOCK_DEBUG_ADD): New macro.
>> (CHECK_RDLOCK): New macro.
>> (CHECK_WRLOCK): New macro.
>> (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
>> (IN_RWLOCK_DEBUG_QUEUE): New macro.
>> (RDLOCK): New macro.
>> (WRLOCK): New macro.
>> (RWUNLOCK): New macro.
>> (RD_TO_WRLOCK): New macro.
>> (INTERN_RDLOCK): New macro.
>> (INTERN_WRLOCK): New macro.
>> (INTERN_RWUNLOCK): New macro.
>> * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
>> a comment.
>> (unit_lock): Remove including associated internal_proto.
>> (unit_rwlock): New declarations including associated internal_proto.
>> (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
>> instead of __gthread_mutex_lock and __gthread_mutex_unlock on
>> unit_lock.
>> * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
>> unit_rwlock instead of LOCK and UNLOCK on unit_lock.
>> (st_write_done_worker): Likewise.
>> * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
>> comment. Use unit_rwlock variable instead of unit_lock variable.
>> (get_gfc_unit_from_unit_root): New function.
>> (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
>> instead of LOCK and UNLOCK on unit_lock.
>> (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
>> LOCK and UNLOCK on unit_lock.
>> (close_units): Likewise.
>> (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
>> unit_lock.
>> * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
>> instead of LOCK and UNLOCK on unit_lock.
>> (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
>> of LOCK and UNLOCK on unit_lock.
>>
>
> It looks like this has broken builds on arm-none-eabi when using newlib:
>
> In file included from /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran
> /runtime/error.c:27:
> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h: In function
> ‘dec_waiting_unlocked’:
> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1023:3: error
> : implicit declaration of function ‘WRLOCK’ [-Wimplicit-function-declaration]
> 1023 | WRLOCK (&unit_rwlock);
> | ^~~~~~
> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1025:3: error
> : implicit declaration of function ‘RWUNLOCK’ [-Wimplicit-function-declaration]
> 1025 | RWUNLOCK (&unit_rwlock);
> | ^~~~~~~~
>
>
> R.
Hi Richard,
The root cause is that the macro WRLOCK and RWUNLOCK are not defined in
io.h. The reason of x86 platform not failed is that
HAVE_ATOMIC_FETCH_ADD is defined then caused above macros were never
been used. Code logic show as below:
#ifdef HAVE_ATOMIC_FETCH_ADD
(void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
#else
WRLOCK (&unit_rwlock);
u->waiting--;
RWUNLOCK (&unit_rwlock);
#endif
I just draft a patch try to fix this bug, because I didn't have arm
platform, would you help to validate if it was fixed on arm platform?
diff --git a/libgfortran/io/io.h b/libgfortran/io/io.h
index 15daa0995b1..c7f0f7d7d9e 100644
--- a/libgfortran/io/io.h
+++ b/libgfortran/io/io.h
@@ -1020,9 +1020,15 @@ dec_waiting_unlocked (gfc_unit *u)
#ifdef HAVE_ATOMIC_FETCH_ADD
(void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
#else
- WRLOCK (&unit_rwlock);
+#ifdef __GTHREAD_RWLOCK_INIT
+ __gthread_rwlock_wrlock (&unit_rwlock);
+ u->waiting--;
+ __gthread_rwlock_unlock (&unit_rwlock);
+#else
+ __gthread_mutex_lock (&unit_rwlock);
u->waiting--;
- RWUNLOCK (&unit_rwlock);
+ __gthread_mutex_unlock (&unit_rwlock);
+#endif
#endif
}
Lipeng Zhu
On 15/12/2023 11:31, Lipeng Zhu wrote:
>
>
> On 2023/12/14 23:50, Richard Earnshaw (lists) wrote:
>> On 09/12/2023 15:39, Lipeng Zhu wrote:
>>> This patch try to introduce the rwlock and split the read/write to
>>> unit_root tree and unit_cache with rwlock instead of the mutex to
>>> increase CPU efficiency. In the get_gfc_unit function, the percentage
>>> to step into the insert_unit function is around 30%, in most instances,
>>> we can get the unit in the phase of reading the unit_cache or unit_root
>>> tree. So split the read/write phase by rwlock would be an approach to
>>> make it more parallel.
>>>
>>> BTW, the IPC metrics can gain around 9x in our test
>>> server with 220 cores. The benchmark we used is
>>> https://github.com/rwesson/NEAT
>>>
>>> libgcc/ChangeLog:
>>>
>>> * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
>>> (__gthrw): New function.
>>> (__gthread_rwlock_rdlock): New function.
>>> (__gthread_rwlock_tryrdlock): New function.
>>> (__gthread_rwlock_wrlock): New function.
>>> (__gthread_rwlock_trywrlock): New function.
>>> (__gthread_rwlock_unlock): New function.
>>>
>>> libgfortran/ChangeLog:
>>>
>>> * io/async.c (DEBUG_LINE): New macro.
>>> * io/async.h (RWLOCK_DEBUG_ADD): New macro.
>>> (CHECK_RDLOCK): New macro.
>>> (CHECK_WRLOCK): New macro.
>>> (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
>>> (IN_RWLOCK_DEBUG_QUEUE): New macro.
>>> (RDLOCK): New macro.
>>> (WRLOCK): New macro.
>>> (RWUNLOCK): New macro.
>>> (RD_TO_WRLOCK): New macro.
>>> (INTERN_RDLOCK): New macro.
>>> (INTERN_WRLOCK): New macro.
>>> (INTERN_RWUNLOCK): New macro.
>>> * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
>>> a comment.
>>> (unit_lock): Remove including associated internal_proto.
>>> (unit_rwlock): New declarations including associated internal_proto.
>>> (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
>>> instead of __gthread_mutex_lock and __gthread_mutex_unlock on
>>> unit_lock.
>>> * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
>>> unit_rwlock instead of LOCK and UNLOCK on unit_lock.
>>> (st_write_done_worker): Likewise.
>>> * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
>>> comment. Use unit_rwlock variable instead of unit_lock variable.
>>> (get_gfc_unit_from_unit_root): New function.
>>> (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
>>> instead of LOCK and UNLOCK on unit_lock.
>>> (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
>>> LOCK and UNLOCK on unit_lock.
>>> (close_units): Likewise.
>>> (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
>>> unit_lock.
>>> * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
>>> instead of LOCK and UNLOCK on unit_lock.
>>> (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
>>> of LOCK and UNLOCK on unit_lock.
>>>
>>
>> It looks like this has broken builds on arm-none-eabi when using newlib:
>>
>> In file included from
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran
>> /runtime/error.c:27:
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h: In
>> function
>> ‘dec_waiting_unlocked’:
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1023:3: error
>> : implicit declaration of function ‘WRLOCK’
>> [-Wimplicit-function-declaration]
>> 1023 | WRLOCK (&unit_rwlock);
>> | ^~~~~~
>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1025:3: error
>> : implicit declaration of function ‘RWUNLOCK’
>> [-Wimplicit-function-declaration]
>> 1025 | RWUNLOCK (&unit_rwlock);
>> | ^~~~~~~~
>>
>>
>> R.
>
> Hi Richard,
>
> The root cause is that the macro WRLOCK and RWUNLOCK are not defined in
> io.h. The reason of x86 platform not failed is that
> HAVE_ATOMIC_FETCH_ADD is defined then caused above macros were never
> been used. Code logic show as below:
> #ifdef HAVE_ATOMIC_FETCH_ADD
> (void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
> #else
> WRLOCK (&unit_rwlock);
> u->waiting--;
> RWUNLOCK (&unit_rwlock);
> #endif
>
> I just draft a patch try to fix this bug, because I didn't have arm
> platform, would you help to validate if it was fixed on arm platform?
>
> diff --git a/libgfortran/io/io.h b/libgfortran/io/io.h
> index 15daa0995b1..c7f0f7d7d9e 100644
> --- a/libgfortran/io/io.h
> +++ b/libgfortran/io/io.h
> @@ -1020,9 +1020,15 @@ dec_waiting_unlocked (gfc_unit *u)
> #ifdef HAVE_ATOMIC_FETCH_ADD
> (void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
> #else
> - WRLOCK (&unit_rwlock);
> +#ifdef __GTHREAD_RWLOCK_INIT
> + __gthread_rwlock_wrlock (&unit_rwlock);
> + u->waiting--;
> + __gthread_rwlock_unlock (&unit_rwlock);
> +#else
> + __gthread_mutex_lock (&unit_rwlock);
> u->waiting--;
> - RWUNLOCK (&unit_rwlock);
> + __gthread_mutex_unlock (&unit_rwlock);
> +#endif
> #endif
> }
>
>
> Lipeng Zhu
Hi Lipeng,
Thanks for the quick reply. I can confirm that with the above change
the bootstrap failure is fixed. However, this shouldn't be considered a
formal review; libgfortran is not really my area.
I'll be away now until January 2nd.
Richard.
Hi!
On 2023-12-13T21:52:29+0100, I wrote:
> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>> On 2023/12/12 1:45, H.J. Lu wrote:
>>> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
>>> > On 2023/12/9 23:23, Jakub Jelinek wrote:
>>> > > On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>>> > > > This patch try to introduce the rwlock and split the read/write to
>>> > > > unit_root tree and unit_cache with rwlock instead of the mutex to
>>> > > > increase CPU efficiency. In the get_gfc_unit function, the
>>> > > > percentage to step into the insert_unit function is around 30%, in
>>> > > > most instances, we can get the unit in the phase of reading the
>>> > > > unit_cache or unit_root tree. So split the read/write phase by
>>> > > > rwlock would be an approach to make it more parallel.
>>> > > >
>>> > > > BTW, the IPC metrics can gain around 9x in our test server with
>>> > > > 220 cores. The benchmark we used is
>>> > > > https://github.com/rwesson/NEAT
>
>>> > > Ok for trunk, thanks.
>
>>> > Thanks! Looking forward to landing to trunk.
>
>>> Pushed for you.
> I've just filed <https://gcc.gnu.org/PR113005>
> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution test timeouts".
> Would you be able to look into that?
See my update in there.
Grüße
Thomas
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
Hi Thomas,
On 2023/12/21 19:42, Thomas Schwinge wrote:
> Hi!
>
> On 2023-12-13T21:52:29+0100, I wrote:
>> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>>> On 2023/12/12 1:45, H.J. Lu wrote:
>>>> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
>>>>> On 2023/12/9 23:23, Jakub Jelinek wrote:
>>>>>> On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>>>>>>> This patch try to introduce the rwlock and split the read/write to
>>>>>>> unit_root tree and unit_cache with rwlock instead of the mutex to
>>>>>>> increase CPU efficiency. In the get_gfc_unit function, the
>>>>>>> percentage to step into the insert_unit function is around 30%, in
>>>>>>> most instances, we can get the unit in the phase of reading the
>>>>>>> unit_cache or unit_root tree. So split the read/write phase by
>>>>>>> rwlock would be an approach to make it more parallel.
>>>>>>>
>>>>>>> BTW, the IPC metrics can gain around 9x in our test server with
>>>>>>> 220 cores. The benchmark we used is
>>>>>>> https://github.com/rwesson/NEAT
>>
>>>>>> Ok for trunk, thanks.
>>
>>>>> Thanks! Looking forward to landing to trunk.
>>
>>>> Pushed for you.
>
>> I've just filed <https://gcc.gnu.org/PR113005>
>> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution test timeouts".
>> Would you be able to look into that?
>
> See my update in there.
>
>
> Grüße
> Thomas
> -------------- > Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße
201, 80634 München; Gesellschaft mit beschränkter Haftung;
Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft:
München; Registergericht München, HRB 106955
>
Since I don't have gcc bugzilla account. Reply in this thread:
Limit themselves to some lower 'OMP_NUM_THREADS' should be an option or
increase the execution timeout?
But I can't reproduce the execution timeout failure on both powerpc9 and
powerpc10 arch machine. And I also tried to decrease the CPU frequency
from 2.6G to 800M, these test cases still can run successfully.
> so only a little bit of an improvement of the new "rwlock"
libgfortran vs. old "mutex" GCC 10 one, curiously. (But supposedly that
depends on the hardware or other factors?)
The rwlock can increase the IPC a lot, maybe the wall time you listed is
not obvious.
$ grep ^cpu < /proc/cpuinfo | uniq -c
192 cpu : POWER10 (architected), altivec supported
Native configuration is powerpc64le-unknown-linux-gnu
Schedule of variations:
unix
PASS: libgomp.fortran/rwlock_1.f90 -O0 (test for excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -O0 execution test
PASS: libgomp.fortran/rwlock_1.f90 -O1 (test for excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -O1 execution test
PASS: libgomp.fortran/rwlock_1.f90 -O2 (test for excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -O2 execution test
PASS: libgomp.fortran/rwlock_1.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions (test for
excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions execution test
PASS: libgomp.fortran/rwlock_1.f90 -O3 -g (test for excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -O3 -g execution test
PASS: libgomp.fortran/rwlock_1.f90 -Os (test for excess errors)
PASS: libgomp.fortran/rwlock_1.f90 -Os execution test
PASS: libgomp.fortran/rwlock_2.f90 -O0 (test for excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -O0 execution test
PASS: libgomp.fortran/rwlock_2.f90 -O1 (test for excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -O1 execution test
PASS: libgomp.fortran/rwlock_2.f90 -O2 (test for excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -O2 execution test
PASS: libgomp.fortran/rwlock_2.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions (test for
excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions execution test
PASS: libgomp.fortran/rwlock_2.f90 -O3 -g (test for excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -O3 -g execution test
PASS: libgomp.fortran/rwlock_2.f90 -Os (test for excess errors)
PASS: libgomp.fortran/rwlock_2.f90 -Os execution test
PASS: libgomp.fortran/rwlock_3.f90 -O0 (test for excess errors)
PASS: libgomp.fortran/rwlock_3.f90 -O0 execution test
PASS: libgomp.fortran/rwlock_3.f90 -O1 (test for excess errors)
PASS: libgomp.fortran/rwlock_3.f90 -O1 execution test
PASS: libgomp.fortran/rwlock_3.f90 -O2 (test for excess errors)
PASS: libgomp.fortran/rwlock_3.f90 -O2 execution test
PASS: libgomp.fortran/rwlock_3.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions (test for
excess errors)
PASS: libgomp.fortran/rwlock_3.f90 -O3 -fomit-frame-pointer
-funroll-loops -fpeel-loops -ftracer -finline-functions execution test
Lipeng Zhu
Hi Lipeng,
It looks like your draft patch to fix the builds for arm-none-eabi target is not merged yet, because our arm-none-eabi builds are still broken. Are you waiting for additional information, or would you be able to fix this issue?
Kind regards,
Vasee
On 2024/1/2 11:57, Vaseeharan Vinayagamoorthy wrote:
> Hi Lipeng,
>
> It looks like your draft patch to fix the builds for arm-none-eabi target is not merged yet, because our arm-none-eabi builds are still broken. Are you waiting for additional information, or would you be able to fix this issue?
>
> Kind regards,
> Vasee
Hi Vasee,
Actually I already sent a patch
https://inbox.sourceware.org/gcc-patches/20231222023605.3894839-1-lipeng.zhu@intel.com/
to fix the build failure issue, now it is waiting for community to review.
Lipeng Zhu
> ________________________________
> From: Richard Earnshaw <Richard.Earnshaw@foss.arm.com>
> Sent: 15 December 2023 19:23
> To: Lipeng Zhu <lipeng.zhu@intel.com>; Richard Earnshaw <Richard.Earnshaw@arm.com>; jakub@redhat.com <jakub@redhat.com>
> Cc: fortran@gcc.gnu.org <fortran@gcc.gnu.org>; gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org>; hongjiu.lu@intel.com <hongjiu.lu@intel.com>; pan.deng@intel.com <pan.deng@intel.com>; rep.dot.nop@gmail.com <rep.dot.nop@gmail.com>; tianyou.li@intel.com <tianyou.li@intel.com>; tkoenig@netcologne.de <tkoenig@netcologne.de>; wangyang.guo@intel.com <wangyang.guo@intel.com>
> Subject: Re: [PATCH v7] libgfortran: Replace mutex with rwlock
>
>
>
> On 15/12/2023 11:31, Lipeng Zhu wrote:
>>
>>
>> On 2023/12/14 23:50, Richard Earnshaw (lists) wrote:
>>> On 09/12/2023 15:39, Lipeng Zhu wrote:
>>>> This patch try to introduce the rwlock and split the read/write to
>>>> unit_root tree and unit_cache with rwlock instead of the mutex to
>>>> increase CPU efficiency. In the get_gfc_unit function, the percentage
>>>> to step into the insert_unit function is around 30%, in most instances,
>>>> we can get the unit in the phase of reading the unit_cache or unit_root
>>>> tree. So split the read/write phase by rwlock would be an approach to
>>>> make it more parallel.
>>>>
>>>> BTW, the IPC metrics can gain around 9x in our test
>>>> server with 220 cores. The benchmark we used is
>>>> https://github.com/rwesson/NEAT
>>>>
>>>> libgcc/ChangeLog:
>>>>
>>>> * gthr-posix.h (__GTHREAD_RWLOCK_INIT): New macro.
>>>> (__gthrw): New function.
>>>> (__gthread_rwlock_rdlock): New function.
>>>> (__gthread_rwlock_tryrdlock): New function.
>>>> (__gthread_rwlock_wrlock): New function.
>>>> (__gthread_rwlock_trywrlock): New function.
>>>> (__gthread_rwlock_unlock): New function.
>>>>
>>>> libgfortran/ChangeLog:
>>>>
>>>> * io/async.c (DEBUG_LINE): New macro.
>>>> * io/async.h (RWLOCK_DEBUG_ADD): New macro.
>>>> (CHECK_RDLOCK): New macro.
>>>> (CHECK_WRLOCK): New macro.
>>>> (TAIL_RWLOCK_DEBUG_QUEUE): New macro.
>>>> (IN_RWLOCK_DEBUG_QUEUE): New macro.
>>>> (RDLOCK): New macro.
>>>> (WRLOCK): New macro.
>>>> (RWUNLOCK): New macro.
>>>> (RD_TO_WRLOCK): New macro.
>>>> (INTERN_RDLOCK): New macro.
>>>> (INTERN_WRLOCK): New macro.
>>>> (INTERN_RWUNLOCK): New macro.
>>>> * io/io.h (struct gfc_unit): Change UNIT_LOCK to UNIT_RWLOCK in
>>>> a comment.
>>>> (unit_lock): Remove including associated internal_proto.
>>>> (unit_rwlock): New declarations including associated internal_proto.
>>>> (dec_waiting_unlocked): Use WRLOCK and RWUNLOCK on unit_rwlock
>>>> instead of __gthread_mutex_lock and __gthread_mutex_unlock on
>>>> unit_lock.
>>>> * io/transfer.c (st_read_done_worker): Use WRLOCK and RWUNLOCK on
>>>> unit_rwlock instead of LOCK and UNLOCK on unit_lock.
>>>> (st_write_done_worker): Likewise.
>>>> * io/unit.c: Change UNIT_LOCK to UNIT_RWLOCK in 'IO locking rules'
>>>> comment. Use unit_rwlock variable instead of unit_lock variable.
>>>> (get_gfc_unit_from_unit_root): New function.
>>>> (get_gfc_unit): Use RDLOCK, WRLOCK and RWUNLOCK on unit_rwlock
>>>> instead of LOCK and UNLOCK on unit_lock.
>>>> (close_unit_1): Use WRLOCK and RWUNLOCK on unit_rwlock instead of
>>>> LOCK and UNLOCK on unit_lock.
>>>> (close_units): Likewise.
>>>> (newunit_alloc): Use RWUNLOCK on unit_rwlock instead of UNLOCK on
>>>> unit_lock.
>>>> * io/unix.c (find_file): Use RDLOCK and RWUNLOCK on unit_rwlock
>>>> instead of LOCK and UNLOCK on unit_lock.
>>>> (flush_all_units): Use WRLOCK and RWUNLOCK on unit_rwlock instead
>>>> of LOCK and UNLOCK on unit_lock.
>>>>
>>>
>>> It looks like this has broken builds on arm-none-eabi when using newlib:
>>>
>>> In file included from
>>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran
>>> /runtime/error.c:27:
>>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h: In
>>> function
>>> ‘dec_waiting_unlocked’:
>>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1023:3: error
>>> : implicit declaration of function ‘WRLOCK’
>>> [-Wimplicit-function-declaration]
>>> 1023 | WRLOCK (&unit_rwlock);
>>> | ^~~~~~
>>> /work/rearnsha/gnusrc/nightly/gcc-cross/master/libgfortran/io/io.h:1025:3: error
>>> : implicit declaration of function ‘RWUNLOCK’
>>> [-Wimplicit-function-declaration]
>>> 1025 | RWUNLOCK (&unit_rwlock);
>>> | ^~~~~~~~
>>>
>>>
>>> R.
>>
>> Hi Richard,
>>
>> The root cause is that the macro WRLOCK and RWUNLOCK are not defined in
>> io.h. The reason of x86 platform not failed is that
>> HAVE_ATOMIC_FETCH_ADD is defined then caused above macros were never
>> been used. Code logic show as below:
>> #ifdef HAVE_ATOMIC_FETCH_ADD
>> (void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
>> #else
>> WRLOCK (&unit_rwlock);
>> u->waiting--;
>> RWUNLOCK (&unit_rwlock);
>> #endif
>>
>> I just draft a patch try to fix this bug, because I didn't have arm
>> platform, would you help to validate if it was fixed on arm platform?
>>
>> diff --git a/libgfortran/io/io.h b/libgfortran/io/io.h
>> index 15daa0995b1..c7f0f7d7d9e 100644
>> --- a/libgfortran/io/io.h
>> +++ b/libgfortran/io/io.h
>> @@ -1020,9 +1020,15 @@ dec_waiting_unlocked (gfc_unit *u)
>> #ifdef HAVE_ATOMIC_FETCH_ADD
>> (void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
>> #else
>> - WRLOCK (&unit_rwlock);
>> +#ifdef __GTHREAD_RWLOCK_INIT
>> + __gthread_rwlock_wrlock (&unit_rwlock);
>> + u->waiting--;
>> + __gthread_rwlock_unlock (&unit_rwlock);
>> +#else
>> + __gthread_mutex_lock (&unit_rwlock);
>> u->waiting--;
>> - RWUNLOCK (&unit_rwlock);
>> + __gthread_mutex_unlock (&unit_rwlock);
>> +#endif
>> #endif
>> }
>>
>>
>> Lipeng Zhu
>
> Hi Lipeng,
>
> Thanks for the quick reply. I can confirm that with the above change
> the bootstrap failure is fixed. However, this shouldn't be considered a
> formal review; libgfortran is not really my area.
>
> I'll be away now until January 2nd.
>
> Richard.
>
On 2023/12/21 19:42, Thomas Schwinge wrote:
> Hi!
>
> On 2023-12-13T21:52:29+0100, I wrote:
>> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>>> On 2023/12/12 1:45, H.J. Lu wrote:
>>>> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com> wrote:
>>>>> On 2023/12/9 23:23, Jakub Jelinek wrote:
>>>>>> On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>>>>>>> This patch try to introduce the rwlock and split the read/write to
>>>>>>> unit_root tree and unit_cache with rwlock instead of the mutex to
>>>>>>> increase CPU efficiency. In the get_gfc_unit function, the
>>>>>>> percentage to step into the insert_unit function is around 30%, in
>>>>>>> most instances, we can get the unit in the phase of reading the
>>>>>>> unit_cache or unit_root tree. So split the read/write phase by
>>>>>>> rwlock would be an approach to make it more parallel.
>>>>>>>
>>>>>>> BTW, the IPC metrics can gain around 9x in our test server with
>>>>>>> 220 cores. The benchmark we used is
>>>>>>> https://github.com/rwesson/NEAT
>>
>>>>>> Ok for trunk, thanks.
>>
>>>>> Thanks! Looking forward to landing to trunk.
>>
>>>> Pushed for you.
>
>> I've just filed <https://gcc.gnu.org/PR113005>
>> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90' execution test timeouts".
>> Would you be able to look into that?
>
> See my update in there.
>
>
> Grüße
> Thomas
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
>
Updated in https://gcc.gnu.org/PR113005. Could you help to verify if the
draft patch would fix the execution test timeout issue on your side?
diff --git a/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
b/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
index f90ecbeb00f..1c271ae031d 100644
--- a/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
+++ b/libgomp/testsuite/libgomp.fortran/rwlock_1.f90
@@ -7,13 +7,12 @@ program main
use omp_lib
implicit none
integer:: unit_number, v1, v2, i
- character(11) :: file_name
+ character(16) :: file_name
character(3) :: async = "no"
!$omp parallel private (unit_number, v1, v2, file_name, async, i)
do i = 0, 100
unit_number = 10 + omp_get_thread_num ()
- write (file_name, "(I3, A)") unit_number, "_tst.dat"
- file_name = adjustl(file_name)
+ write (file_name, "(I5.5, A)") unit_number, "_tst.dat"
open (unit_number, file=file_name, asynchronous="yes")
! call inquire with file parameter to test find_file in unix.c
inquire (file=file_name, asynchronous=async)
Lipeng Zhu
On 1/3/2024 5:14 PM, Lipeng Zhu wrote:
>
>
> On 2023/12/21 19:42, Thomas Schwinge wrote:
>> Hi!
>>
>> On 2023-12-13T21:52:29+0100, I wrote:
>>> On 2023-12-12T02:05:26+0000, "Zhu, Lipeng" <lipeng.zhu@intel.com> wrote:
>>>> On 2023/12/12 1:45, H.J. Lu wrote:
>>>>> On Sat, Dec 9, 2023 at 7:25 PM Zhu, Lipeng <lipeng.zhu@intel.com>
>>>>> wrote:
>>>>>> On 2023/12/9 23:23, Jakub Jelinek wrote:
>>>>>>> On Sat, Dec 09, 2023 at 10:39:45AM -0500, Lipeng Zhu wrote:
>>>>>>>> This patch try to introduce the rwlock and split the read/write to
>>>>>>>> unit_root tree and unit_cache with rwlock instead of the mutex to
>>>>>>>> increase CPU efficiency. In the get_gfc_unit function, the
>>>>>>>> percentage to step into the insert_unit function is around 30%, in
>>>>>>>> most instances, we can get the unit in the phase of reading the
>>>>>>>> unit_cache or unit_root tree. So split the read/write phase by
>>>>>>>> rwlock would be an approach to make it more parallel.
>>>>>>>>
>>>>>>>> BTW, the IPC metrics can gain around 9x in our test server with
>>>>>>>> 220 cores. The benchmark we used is
>>>>>>>> https://github.com/rwesson/NEAT
>>>
>>>>>>> Ok for trunk, thanks.
>>>
>>>>>> Thanks! Looking forward to landing to trunk.
>>>
>>>>> Pushed for you.
>>
>>> I've just filed <https://gcc.gnu.org/PR113005>
>>> "'libgomp.fortran/rwlock_1.f90', 'libgomp.fortran/rwlock_3.f90'
>>> execution test timeouts".
>>> Would you be able to look into that?
>>
>> See my update in there.
>>
>>
>> Grüße
>> Thomas
>> -----------------
>> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße
>> 201, 80634 München; Gesellschaft mit beschränkter Haftung;
>> Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft:
>> München; Registergericht München, HRB 106955
>>
>
> Updated in https://gcc.gnu.org/PR113005. Could you help to verify if the
> draft patch would fix the execution test timeout issue on your side?
>
Hi Thomas,
Any feedback from your side?
Regards,
Lipeng Zhu
@@ -48,6 +48,9 @@ typedef pthread_t __gthread_t;
typedef pthread_key_t __gthread_key_t;
typedef pthread_once_t __gthread_once_t;
typedef pthread_mutex_t __gthread_mutex_t;
+#ifndef __cplusplus
+typedef pthread_rwlock_t __gthread_rwlock_t;
+#endif
typedef pthread_mutex_t __gthread_recursive_mutex_t;
typedef pthread_cond_t __gthread_cond_t;
typedef struct timespec __gthread_time_t;
@@ -58,6 +61,9 @@ typedef struct timespec __gthread_time_t;
#define __GTHREAD_MUTEX_INIT PTHREAD_MUTEX_INITIALIZER
#define __GTHREAD_MUTEX_INIT_FUNCTION __gthread_mutex_init_function
+#ifndef __cplusplus
+#define __GTHREAD_RWLOCK_INIT PTHREAD_RWLOCK_INITIALIZER
+#endif
#define __GTHREAD_ONCE_INIT PTHREAD_ONCE_INIT
#if defined(PTHREAD_RECURSIVE_MUTEX_INITIALIZER)
#define __GTHREAD_RECURSIVE_MUTEX_INIT PTHREAD_RECURSIVE_MUTEX_INITIALIZER
@@ -135,6 +141,13 @@ __gthrw(pthread_mutexattr_init)
__gthrw(pthread_mutexattr_settype)
__gthrw(pthread_mutexattr_destroy)
+#ifndef __cplusplus
+__gthrw(pthread_rwlock_rdlock)
+__gthrw(pthread_rwlock_tryrdlock)
+__gthrw(pthread_rwlock_wrlock)
+__gthrw(pthread_rwlock_trywrlock)
+__gthrw(pthread_rwlock_unlock)
+#endif
#if defined(_LIBOBJC) || defined(_LIBOBJC_WEAK)
/* Objective-C. */
@@ -885,6 +898,53 @@ __gthread_cond_destroy (__gthread_cond_t* __cond)
return __gthrw_(pthread_cond_destroy) (__cond);
}
+#ifndef __cplusplus
+static inline int
+__gthread_rwlock_rdlock (__gthread_rwlock_t *__rwlock)
+{
+ if (__gthread_active_p ())
+ return __gthrw_(pthread_rwlock_rdlock) (__rwlock);
+ else
+ return 0;
+}
+
+static inline int
+__gthread_rwlock_tryrdlock (__gthread_rwlock_t *__rwlock)
+{
+ if (__gthread_active_p ())
+ return __gthrw_(pthread_rwlock_tryrdlock) (__rwlock);
+ else
+ return 0;
+}
+
+static inline int
+__gthread_rwlock_wrlock (__gthread_rwlock_t *__rwlock)
+{
+ if (__gthread_active_p ())
+ return __gthrw_(pthread_rwlock_wrlock) (__rwlock);
+ else
+ return 0;
+}
+
+static inline int
+__gthread_rwlock_trywrlock (__gthread_rwlock_t *__rwlock)
+{
+ if (__gthread_active_p ())
+ return __gthrw_(pthread_rwlock_trywrlock) (__rwlock);
+ else
+ return 0;
+}
+
+static inline int
+__gthread_rwlock_unlock (__gthread_rwlock_t *__rwlock)
+{
+ if (__gthread_active_p ())
+ return __gthrw_(pthread_rwlock_unlock) (__rwlock);
+ else
+ return 0;
+}
+#endif
+
#endif /* _LIBOBJC */
#endif /* ! GCC_GTHR_POSIX_H */
@@ -42,6 +42,10 @@ DEBUG_LINE (__thread const char *aio_prefix = MPREFIX);
DEBUG_LINE (__gthread_mutex_t debug_queue_lock = __GTHREAD_MUTEX_INIT;)
DEBUG_LINE (aio_lock_debug *aio_debug_head = NULL;)
+#ifdef __GTHREAD_RWLOCK_INIT
+DEBUG_LINE (aio_rwlock_debug *aio_rwlock_debug_head = NULL;)
+DEBUG_LINE (__gthread_rwlock_t debug_queue_rwlock = __GTHREAD_RWLOCK_INIT;)
+#endif
/* Current unit for asynchronous I/O. Needed for error reporting. */
@@ -210,6 +210,128 @@
DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #mutex, mutex); \
} while (0)
+#ifdef __GTHREAD_RWLOCK_INIT
+#define RWLOCK_DEBUG_ADD(rwlock) do { \
+ aio_rwlock_debug *n; \
+ n = xmalloc (sizeof (aio_rwlock_debug)); \
+ n->prev = TAIL_RWLOCK_DEBUG_QUEUE; \
+ if (n->prev) \
+ n->prev->next = n; \
+ n->next = NULL; \
+ n->line = __LINE__; \
+ n->func = __FUNCTION__; \
+ n->rw = rwlock; \
+ if (!aio_rwlock_debug_head) { \
+ aio_rwlock_debug_head = n; \
+ } \
+ } while (0)
+
+#define CHECK_RDLOCK(rwlock, status) do { \
+ aio_rwlock_debug *curr; \
+ INTERN_WRLOCK (&debug_queue_rwlock); \
+ if (__gthread_rwlock_tryrdlock (rwlock)) { \
+ if ((curr = IN_RWLOCK_DEBUG_QUEUE (rwlock))) { \
+ sprintf (status, DEBUG_RED "%s():%d" DEBUG_NORM, curr->func, curr->line); \
+ } else \
+ sprintf (status, DEBUG_RED "unknown" DEBUG_NORM); \
+ } \
+ else { \
+ __gthread_rwlock_unlock (rwlock); \
+ sprintf (status, DEBUG_GREEN "rwunlocked" DEBUG_NORM); \
+ } \
+ INTERN_RWUNLOCK (&debug_queue_rwlock); \
+ }while (0)
+
+#define CHECK_WRLOCK(rwlock, status) do { \
+ aio_rwlock_debug *curr; \
+ INTERN_WRLOCK (&debug_queue_rwlock); \
+ if (__gthread_rwlock_trywrlock (rwlock)) { \
+ if ((curr = IN_RWLOCK_DEBUG_QUEUE (rwlock))) { \
+ sprintf (status, DEBUG_RED "%s():%d" DEBUG_NORM, curr->func, curr->line); \
+ } else \
+ sprintf (status, DEBUG_RED "unknown" DEBUG_NORM); \
+ } \
+ else { \
+ __gthread_rwlock_unlock (rwlock); \
+ sprintf (status, DEBUG_GREEN "rwunlocked" DEBUG_NORM); \
+ } \
+ INTERN_RWUNLOCK (&debug_queue_rwlock); \
+ }while (0)
+
+#define TAIL_RWLOCK_DEBUG_QUEUE ({ \
+ aio_rwlock_debug *curr = aio_rwlock_debug_head; \
+ while (curr && curr->next) { \
+ curr = curr->next; \
+ } \
+ curr; \
+ })
+
+#define IN_RWLOCK_DEBUG_QUEUE(rwlock) ({ \
+ __label__ end; \
+ aio_rwlock_debug *curr = aio_rwlock_debug_head; \
+ while (curr) { \
+ if (curr->rw == rwlock) { \
+ goto end; \
+ } \
+ curr = curr->next; \
+ } \
+ end:; \
+ curr; \
+ })
+
+#define RDLOCK(rwlock) do { \
+ char status[200]; \
+ CHECK_RDLOCK (rwlock, status); \
+ DEBUG_PRINTF ("%s%-42s prev: %-35s %20s():%-5d %18p\n", aio_prefix, \
+ DEBUG_RED "RDLOCK: " DEBUG_NORM #rwlock, status, __FUNCTION__, __LINE__, (void *) rwlock); \
+ INTERN_RDLOCK (rwlock); \
+ INTERN_WRLOCK (&debug_queue_rwlock); \
+ RWLOCK_DEBUG_ADD (rwlock); \
+ INTERN_RWUNLOCK (&debug_queue_rwlock); \
+ DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #rwlock, rwlock); \
+ } while (0)
+
+#define WRLOCK(rwlock) do { \
+ char status[200]; \
+ CHECK_WRLOCK (rwlock, status); \
+ DEBUG_PRINTF ("%s%-42s prev: %-35s %20s():%-5d %18p\n", aio_prefix, \
+ DEBUG_RED "WRLOCK: " DEBUG_NORM #rwlock, status, __FUNCTION__, __LINE__, (void *) rwlock); \
+ INTERN_WRLOCK (rwlock); \
+ INTERN_WRLOCK (&debug_queue_rwlock); \
+ RWLOCK_DEBUG_ADD (rwlock); \
+ INTERN_RWUNLOCK (&debug_queue_rwlock); \
+ DEBUG_PRINTF ("%s" DEBUG_RED "ACQ:" DEBUG_NORM " %-30s %78p\n", aio_prefix, #rwlock, rwlock); \
+ } while (0)
+
+#define RWUNLOCK(rwlock) do { \
+ aio_rwlock_debug *curr; \
+ DEBUG_PRINTF ("%s%-75s %20s():%-5d %18p\n", aio_prefix, DEBUG_GREEN "RWUNLOCK: " DEBUG_NORM #rwlock, \
+ __FUNCTION__, __LINE__, (void *) rwlock); \
+ INTERN_WRLOCK (&debug_queue_rwlock); \
+ curr = IN_RWLOCK_DEBUG_QUEUE (rwlock); \
+ if (curr) \
+ { \
+ if (curr->prev) \
+ curr->prev->next = curr->next; \
+ if (curr->next) { \
+ curr->next->prev = curr->prev; \
+ if (curr == aio_rwlock_debug_head) \
+ aio_rwlock_debug_head = curr->next; \
+ } else { \
+ if (curr == aio_rwlock_debug_head) \
+ aio_rwlock_debug_head = NULL; \
+ } \
+ free (curr); \
+ } \
+ INTERN_RWUNLOCK (&debug_queue_rwlock); \
+ INTERN_RWUNLOCK (rwlock); \
+ } while (0)
+
+#define RD_TO_WRLOCK(rwlock) \
+ RWUNLOCK (rwlock); \
+ WRLOCK (rwlock);
+#endif
+
#define DEBUG_LINE(...) __VA_ARGS__
#else
@@ -221,12 +343,31 @@
#define LOCK(mutex) INTERN_LOCK (mutex)
#define UNLOCK(mutex) INTERN_UNLOCK (mutex)
#define TRYLOCK(mutex) (__gthread_mutex_trylock (mutex))
+#ifdef __GTHREAD_RWLOCK_INIT
+#define RDLOCK(rwlock) INTERN_RDLOCK (rwlock)
+#define WRLOCK(rwlock) INTERN_WRLOCK (rwlock)
+#define RWUNLOCK(rwlock) INTERN_RWUNLOCK (rwlock)
+#define RD_TO_WRLOCK(rwlock) \
+ RWUNLOCK (rwlock); \
+ WRLOCK (rwlock);
+#endif
+#endif
+
+#ifndef __GTHREAD_RWLOCK_INIT
+#define RDLOCK(rwlock) LOCK (rwlock)
+#define WRLOCK(rwlock) LOCK (rwlock)
+#define RWUNLOCK(rwlock) UNLOCK (rwlock)
+#define RD_TO_WRLOCK(rwlock) do {} while (0)
#endif
#define INTERN_LOCK(mutex) T_ERROR (__gthread_mutex_lock, mutex);
#define INTERN_UNLOCK(mutex) T_ERROR (__gthread_mutex_unlock, mutex);
+#define INTERN_RDLOCK(rwlock) T_ERROR (__gthread_rwlock_rdlock, rwlock)
+#define INTERN_WRLOCK(rwlock) T_ERROR (__gthread_rwlock_wrlock, rwlock)
+#define INTERN_RWUNLOCK(rwlock) T_ERROR (__gthread_rwlock_unlock, rwlock)
+
#if ASYNC_IO
/* au->lock has to be held when calling this macro. */
@@ -288,8 +429,18 @@ DEBUG_LINE (typedef struct aio_lock_debug{
struct aio_lock_debug *prev;
} aio_lock_debug;)
+DEBUG_LINE (typedef struct aio_rwlock_debug{
+ __gthread_rwlock_t *rw;
+ int line;
+ const char *func;
+ struct aio_rwlock_debug *next;
+ struct aio_rwlock_debug *prev;
+} aio_rwlock_debug;)
+
DEBUG_LINE (extern aio_lock_debug *aio_debug_head;)
DEBUG_LINE (extern __gthread_mutex_t debug_queue_lock;)
+DEBUG_LINE (extern aio_rwlock_debug *aio_rwlock_debug_head;)
+DEBUG_LINE (extern __gthread_rwlock_t debug_queue_rwlock;)
/* Thread - local storage of the current unit we are looking at. Needed for
error reporting. */
@@ -690,7 +690,7 @@ typedef struct gfc_unit
from the UNIT_ROOT tree, but doesn't free it and the
last of the waiting threads will do that.
This must be either atomically increased/decreased, or
- always guarded by UNIT_LOCK. */
+ always guarded by UNIT_RWLOCK. */
int waiting;
/* Flag set by close_unit if the unit as been closed.
Must be manipulated under unit's lock. */
@@ -769,8 +769,13 @@ internal_proto(default_recl);
extern gfc_unit *unit_root;
internal_proto(unit_root);
-extern __gthread_mutex_t unit_lock;
-internal_proto(unit_lock);
+#ifdef __GTHREAD_RWLOCK_INIT
+extern __gthread_rwlock_t unit_rwlock;
+internal_proto(unit_rwlock);
+#else
+extern __gthread_mutex_t unit_rwlock;
+internal_proto(unit_rwlock);
+#endif
extern int close_unit (gfc_unit *);
internal_proto(close_unit);
@@ -1015,9 +1020,9 @@ dec_waiting_unlocked (gfc_unit *u)
#ifdef HAVE_ATOMIC_FETCH_ADD
(void) __atomic_fetch_add (&u->waiting, -1, __ATOMIC_RELAXED);
#else
- __gthread_mutex_lock (&unit_lock);
+ WRLOCK (&unit_rwlock);
u->waiting--;
- __gthread_mutex_unlock (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
#endif
}
@@ -4538,9 +4538,9 @@ st_read_done_worker (st_parameter_dt *dtp, bool unlock)
if (free_newunit)
{
/* Avoid inverse lock issues by placing after unlock_unit. */
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
newunit_free (dtp->common.unit);
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
}
}
@@ -4634,9 +4634,9 @@ st_write_done_worker (st_parameter_dt *dtp, bool unlock)
if (free_newunit)
{
/* Avoid inverse lock issues by placing after unlock_unit. */
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
newunit_free (dtp->common.unit);
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
}
}
@@ -33,34 +33,36 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
/* IO locking rules:
- UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
+ UNIT_RWLOCK is a master rw lock, protecting UNIT_ROOT tree and UNIT_CACHE.
+ Using an rwlock improves efficiency by allowing us to separate readers
+ and writers of both UNIT_ROOT and UNIT_CACHE.
Concurrent use of different units should be supported, so
each unit has its own lock, LOCK.
Open should be atomic with its reopening of units and list_read.c
in several places needs find_unit another unit while holding stdin
- unit's lock, so it must be possible to acquire UNIT_LOCK while holding
+ unit's lock, so it must be possible to acquire UNIT_RWLOCK while holding
some unit's lock. Therefore to avoid deadlocks, it is forbidden
- to acquire unit's private locks while holding UNIT_LOCK, except
+ to acquire unit's private locks while holding UNIT_RWLOCK, except
for freshly created units (where no other thread can get at their
address yet) or when using just trylock rather than lock operation.
In addition to unit's private lock each unit has a WAITERS counter
and CLOSED flag. WAITERS counter must be either only
atomically incremented/decremented in all places (if atomic builtins
- are supported), or protected by UNIT_LOCK in all places (otherwise).
+ are supported), or protected by UNIT_RWLOCK in all places (otherwise).
CLOSED flag must be always protected by unit's LOCK.
- After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
+ After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_RWLOCK held,
WAITERS must be incremented to avoid concurrent close from freeing
- the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
- Unit freeing is always done under UNIT_LOCK. If close_unit sees any
+ the unit between unlocking UNIT_RWLOCK and acquiring unit's LOCK.
+ Unit freeing is always done under UNIT_RWLOCK. If close_unit sees any
WAITERS, it doesn't free the unit but instead sets the CLOSED flag
and the thread that decrements WAITERS to zero while CLOSED flag is
- set is responsible for freeing it (while holding UNIT_LOCK).
+ set is responsible for freeing it (while holding UNIT_RWLOCK).
flush_all_units operation is iterating over the unit tree with
- increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
+ increasing UNIT_NUMBER while holding UNIT_RWLOCK and attempting to
flush each unit (and therefore needs the unit's LOCK held as well).
To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
- remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
- unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
+ remembers the current unit's UNIT_NUMBER, unlocks UNIT_RWLOCK, acquires
+ unit's LOCK and after flushing reacquires UNIT_RWLOCK and restarts with
the smallest UNIT_NUMBER above the last one flushed.
If find_unit/find_or_create_unit/find_file/get_unit routines return
@@ -101,10 +103,14 @@ gfc_offset max_offset;
gfc_offset default_recl;
gfc_unit *unit_root;
+#ifdef __GTHREAD_RWLOCK_INIT
+__gthread_rwlock_t unit_rwlock = __GTHREAD_RWLOCK_INIT;
+#else
#ifdef __GTHREAD_MUTEX_INIT
-__gthread_mutex_t unit_lock = __GTHREAD_MUTEX_INIT;
+__gthread_mutex_t unit_rwlock = __GTHREAD_MUTEX_INIT;
#else
-__gthread_mutex_t unit_lock;
+__gthread_mutex_t unit_rwlock;
+#endif
#endif
/* We use these filenames for error reporting. */
@@ -317,6 +323,28 @@ delete_unit (gfc_unit *old)
unit_root = delete_treap (old, unit_root);
}
+/* get_gfc_unit_from_root()-- Given an integer, return a pointer
+ to the unit structure. Returns NULL if the unit does not exist,
+ otherwise returns a locked unit. */
+
+static inline gfc_unit *
+get_gfc_unit_from_unit_root (int n)
+{
+ gfc_unit *p;
+ int c = 0;
+ p = unit_root;
+ while (p != NULL)
+ {
+ c = compare (n, p->unit_number);
+ if (c < 0)
+ p = p->left;
+ if (c > 0)
+ p = p->right;
+ if (c == 0)
+ break;
+ }
+ return p;
+}
/* get_gfc_unit()-- Given an integer, return a pointer to the unit
structure. Returns NULL if the unit does not exist,
@@ -329,7 +357,7 @@ get_gfc_unit (int n, int do_create)
int c, created = 0;
NOTE ("Unit n=%d, do_create = %d", n, do_create);
- LOCK (&unit_lock);
+ RDLOCK (&unit_rwlock);
retry:
for (c = 0; c < CACHE_SIZE; c++)
@@ -339,18 +367,25 @@ retry:
goto found;
}
- p = unit_root;
- while (p != NULL)
- {
- c = compare (n, p->unit_number);
- if (c < 0)
- p = p->left;
- if (c > 0)
- p = p->right;
- if (c == 0)
- break;
- }
-
+ p = get_gfc_unit_from_unit_root (n);
+
+ /* We did not find a unit in the cache nor in the unit list,
+ create a new (locked) unit and insert into the unit list and
+ cache. Manipulating either or both the unit list and the unit
+ cache requires to hold a write-lock [for obvious reasons]:
+ By separating the read/write lock, we will greatly reduce
+ the contention on the read part, while the write part is
+ unlikely once the unit hits the cache. */
+ RD_TO_WRLOCK (&unit_rwlock);
+
+ /* In the case of high concurrency, when multiple threads want
+ to find or create the same unit, the unit number may not
+ exist in cache nor in the unit list during read phase, then
+ threads will acquire the write-lock to insert the same unit
+ number to unit list. To avoid duplicate insert, we need to
+ find unit list once again to ensure that the unit number
+ not exist. */
+ p = get_gfc_unit_from_unit_root (n);
if (p == NULL && do_create)
{
p = insert_unit (n);
@@ -368,8 +403,8 @@ retry:
if (created)
{
/* Newly created units have their lock held already
- from insert_unit. Just unlock UNIT_LOCK and return. */
- UNLOCK (&unit_lock);
+ from insert_unit. Just unlock UNIT_RWLOCK and return. */
+ RWUNLOCK (&unit_rwlock);
return p;
}
@@ -380,7 +415,7 @@ found:
if (! TRYLOCK (&p->lock))
{
/* assert (p->closed == 0); */
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
return p;
}
@@ -388,14 +423,14 @@ found:
}
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
if (p != NULL && (p->child_dtio == 0))
{
LOCK (&p->lock);
if (p->closed)
{
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
UNLOCK (&p->lock);
if (predec_waiting_locked (p) == 0)
destroy_unit_mutex (p);
@@ -594,8 +629,8 @@ init_units (void)
#endif
#endif
-#ifndef __GTHREAD_MUTEX_INIT
- __GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock);
+#if (!defined(__GTHREAD_RWLOCK_INIT) && !defined(__GTHREAD_MUTEX_INIT))
+ __GTHREAD_MUTEX_INIT_FUNCTION (&unit_rwlock);
#endif
if (sizeof (max_offset) == 8)
@@ -732,7 +767,7 @@ close_unit_1 (gfc_unit *u, int locked)
u->closed = 1;
if (!locked)
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
for (i = 0; i < CACHE_SIZE; i++)
if (unit_cache[i] == u)
@@ -759,7 +794,7 @@ close_unit_1 (gfc_unit *u, int locked)
destroy_unit_mutex (u);
if (!locked)
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
return rc;
}
@@ -796,10 +831,10 @@ close_unit (gfc_unit *u)
void
close_units (void)
{
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
while (unit_root != NULL)
close_unit_1 (unit_root, 1);
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
free (newunits);
@@ -906,7 +941,7 @@ finish_last_advance_record (gfc_unit *u)
int
newunit_alloc (void)
{
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
if (!newunits)
{
newunits = xcalloc (16, 1);
@@ -920,7 +955,7 @@ newunit_alloc (void)
{
newunits[ii] = true;
newunit_lwi = ii + 1;
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
return -ii + NEWUNIT_START;
}
}
@@ -933,12 +968,12 @@ newunit_alloc (void)
memset (newunits + old_size, 0, old_size);
newunits[old_size] = true;
newunit_lwi = old_size + 1;
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
return -old_size + NEWUNIT_START;
}
-/* Free a previously allocated newunit= unit number. unit_lock must
+/* Free a previously allocated newunit= unit number. unit_rwlock must
be held when calling. */
void
@@ -1773,7 +1773,7 @@ find_file (const char *file, gfc_charlen_type file_len)
id = id_from_path (path);
#endif
- LOCK (&unit_lock);
+ RDLOCK (&unit_rwlock);
retry:
u = find_file0 (unit_root, FIND_FILE0_ARGS);
if (u != NULL)
@@ -1782,19 +1782,19 @@ retry:
if (! __gthread_mutex_trylock (&u->lock))
{
/* assert (u->closed == 0); */
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
goto done;
}
inc_waiting_locked (u);
}
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
if (u != NULL)
{
LOCK (&u->lock);
if (u->closed)
{
- LOCK (&unit_lock);
+ RDLOCK (&unit_rwlock);
UNLOCK (&u->lock);
if (predec_waiting_locked (u) == 0)
free (u);
@@ -1838,13 +1838,13 @@ flush_all_units (void)
gfc_unit *u;
int min_unit = 0;
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
do
{
u = flush_all_units_1 (unit_root, min_unit);
if (u != NULL)
inc_waiting_locked (u);
- UNLOCK (&unit_lock);
+ RWUNLOCK (&unit_rwlock);
if (u == NULL)
return;
@@ -1855,13 +1855,13 @@ flush_all_units (void)
if (u->closed == 0)
{
sflush (u->s);
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
UNLOCK (&u->lock);
(void) predec_waiting_locked (u);
}
else
{
- LOCK (&unit_lock);
+ WRLOCK (&unit_rwlock);
UNLOCK (&u->lock);
if (predec_waiting_locked (u) == 0)
free (u);
new file mode 100644
@@ -0,0 +1,33 @@
+! { dg-do run }
+! Multiple threads call open/write/read/close in concurrency with different unit number,
+! threads can acquire read lock concurrently, to find unit from cache or unit list very frequently,
+! if not found, threads will acquire the write lock exclusively to insert unit to cache and unit list.
+! This test case is used to stress both the read and write lock when access unit cache and list.
+program main
+ use omp_lib
+ implicit none
+ integer:: unit_number, v1, v2, i
+ character(11) :: file_name
+ character(3) :: async = "no"
+ !$omp parallel private (unit_number, v1, v2, file_name, async, i)
+ do i = 0, 100
+ unit_number = 10 + omp_get_thread_num ()
+ write (file_name, "(I3, A)") unit_number, "_tst.dat"
+ file_name = adjustl(file_name)
+ open (unit_number, file=file_name, asynchronous="yes")
+ ! call inquire with file parameter to test find_file in unix.c
+ inquire (file=file_name, asynchronous=async)
+ if (async /= "YES") stop 1
+ write (unit_number, *, asynchronous="yes") unit_number
+ write (unit_number, *, asynchronous="yes") unit_number + 1
+ close(unit_number)
+
+ open (unit_number, file = file_name, asynchronous="yes")
+ read (unit_number, *, asynchronous="yes") v1
+ read (unit_number, *, asynchronous="yes") v2
+ wait (unit_number)
+ if ((v1 /= unit_number) .or. (v2 /= unit_number + 1)) stop 2
+ close(unit_number, status="delete")
+ end do
+ !$omp end parallel
+end program
new file mode 100644
@@ -0,0 +1,22 @@
+! { dg-do run }
+! Insert a unit into cache at the beginning, then start multiple
+! threads to access the same unit concurrency, unit will be found in unit cache during the read lock phase.
+! This test case is used to test the read lock when access unit cache and list.
+program main
+ use omp_lib
+ implicit none
+ integer:: thread_id, total_threads, i, j
+ total_threads = omp_get_max_threads ()
+ open (10, file='tst.dat', asynchronous="yes")
+ !$omp parallel private (thread_id, i, j)
+ do i = 1, 100
+ thread_id = omp_get_thread_num ()
+ do j = 1, 100
+ write (10, *, asynchronous="yes") thread_id, i
+ end do
+ end do
+ !$omp end parallel
+ ! call inquire with file parameter to test find_file in unix.c
+ call flush ()
+ close (10, status="delete")
+end program
new file mode 100644
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+! { dg-do run }
+! Find or create the same unit number in concurrency,
+! at beginning, threads cannot find the unit in cache or unit list,
+! then threads will acquire the write lock to insert unit.
+! This test case is used to ensure that no duplicate unit number will be
+! inserted into cache nor unit list when same unit was accessed in concurrency.
+program main
+ use omp_lib
+ implicit none
+ integer:: i
+ !$omp parallel private (i)
+ do i = 1, 100
+ open (10, file='tst.dat', asynchronous="yes")
+ ! Delete the unit number from cache and unit list to stress write lock.
+ close (10, status="delete")
+ end do
+ !$omp end parallel
+end program