diff mbox series

perf test: Fix session topology test on heterogeneous systems

Message ID 20240122155436.185089-1-james.clark@arm.com
State New
Headers
Series perf test: Fix session topology test on heterogeneous systems |

Commit Message

James Clark Jan. 22, 2024, 3:54 p.m. UTC 
  The test currently fails with this message when evlist__new_default()
opens more than one event:

  32: Session topology                                                :
  --- start ---
  templ file: /tmp/perf-test-vv5YzZ
  Using CPUID 0x00000000410fd070
  Opening: unknown-hardware:HG
  ------------------------------------------------------------
  perf_event_attr:
    type                             0 (PERF_TYPE_HARDWARE)
    config                           0xb00000000
    disabled                         1
  ------------------------------------------------------------
  sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 4
  Opening: unknown-hardware:HG
  ------------------------------------------------------------
  perf_event_attr:
    type                             0 (PERF_TYPE_HARDWARE)
    config                           0xa00000000
    disabled                         1
  ------------------------------------------------------------
  sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 5
  non matching sample_type
  FAILED tests/topology.c:73 can't get session
  ---- end ----
  Session topology: FAILED!

This is because when re-opening the file and parsing the header, Perf
expects that any file that has more than one event has the session ID
flag set. Perf record already sets the flag in a similar way when there
is more than one event, so add the same logic to evlist__new_default().

evlist__new_default() is only currently used in tests, so I don't
expect this change to have any other side effects.

The session topology test has been failing on Arm big.LITTLE platforms
since commit 251aa040244a ("perf parse-events: Wildcard most
"numeric" events") when evlist__new_default() started opening multiple
events for 'cycles'.

Fixes: 251aa040244a ("perf parse-events: Wildcard most "numeric" events")
Signed-off-by: James Clark <james.clark@arm.com>
---
 tools/perf/util/evlist.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

James Clark Jan. 22, 2024, 3:58 p.m. UTC | #1 
On 22/01/2024 15:54, James Clark wrote:
> The test currently fails with this message when evlist__new_default()
> opens more than one event:
> 
>   32: Session topology                                                :
>   --- start ---
>   templ file: /tmp/perf-test-vv5YzZ
>   Using CPUID 0x00000000410fd070
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xb00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 4
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xa00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 5
>   non matching sample_type
>   FAILED tests/topology.c:73 can't get session
>   ---- end ----
>   Session topology: FAILED!
> 
> This is because when re-opening the file and parsing the header, Perf
> expects that any file that has more than one event has the session ID

session ID -> sample ID
Liang, Kan Jan. 22, 2024, 4:41 p.m. UTC | #2 
On 2024-01-22 10:54 a.m., James Clark wrote:
> The test currently fails with this message when evlist__new_default()
> opens more than one event:
> 
>   32: Session topology                                                :
>   --- start ---
>   templ file: /tmp/perf-test-vv5YzZ
>   Using CPUID 0x00000000410fd070
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xb00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 4
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xa00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 5
>   non matching sample_type
>   FAILED tests/topology.c:73 can't get session
>   ---- end ----
>   Session topology: FAILED!
> 
> This is because when re-opening the file and parsing the header, Perf
> expects that any file that has more than one event has the session ID
> flag set. Perf record already sets the flag in a similar way when there
> is more than one event, so add the same logic to evlist__new_default().
> 
> evlist__new_default() is only currently used in tests, so I don't
> expect this change to have any other side effects.
> 
> The session topology test has been failing on Arm big.LITTLE platforms
> since commit 251aa040244a ("perf parse-events: Wildcard most
> "numeric" events") when evlist__new_default() started opening multiple
> events for 'cycles'.
> 
> Fixes: 251aa040244a ("perf parse-events: Wildcard most "numeric" events")
> Signed-off-by: James Clark <james.clark@arm.com>
Verified on an Intel hybrid machine.

Tested-by: Kan Liang <kan.liang@linux.intel.com>

Thanks,
Kan


> ---
>  tools/perf/util/evlist.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 95f25e9fb994..56db37fac6f6 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -95,6 +95,7 @@ struct evlist *evlist__new_default(void)
>  	struct evlist *evlist = evlist__new();
>  	bool can_profile_kernel;
>  	int err;
> +	struct evsel *evsel;
>  
>  	if (!evlist)
>  		return NULL;
> @@ -106,6 +107,10 @@ struct evlist *evlist__new_default(void)
>  		evlist = NULL;
>  	}
>  
> +	if (evlist->core.nr_entries > 1)
> +		evlist__for_each_entry(evlist, evsel)
> +			evsel__set_sample_id(evsel, false);
> +
>  	return evlist;
>  }
>
Ian Rogers Jan. 22, 2024, 5:09 p.m. UTC | #3 
Hi James, I think the subject should be something like "perf evlist:
Fix new_default for >1 core PMU" as the change will apply more widely
than just the test. The test failure fix can be in the subject. You
could add a:

Closes: https://lore.kernel.org/lkml/CAP-5=fWVQ-7ijjK3-w1q+k2WYVNHbAcejb-xY0ptbjRw476VKA@mail.gmail.com/

On Mon, Jan 22, 2024 at 7:55 AM James Clark <james.clark@arm.com> wrote:
>
> The test currently fails with this message when evlist__new_default()
> opens more than one event:
>
>   32: Session topology                                                :
>   --- start ---
>   templ file: /tmp/perf-test-vv5YzZ
>   Using CPUID 0x00000000410fd070
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xb00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 4
>   Opening: unknown-hardware:HG
>   ------------------------------------------------------------
>   perf_event_attr:
>     type                             0 (PERF_TYPE_HARDWARE)
>     config                           0xa00000000
>     disabled                         1
>   ------------------------------------------------------------
>   sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 5
>   non matching sample_type
>   FAILED tests/topology.c:73 can't get session
>   ---- end ----
>   Session topology: FAILED!
>
> This is because when re-opening the file and parsing the header, Perf
> expects that any file that has more than one event has the session ID
> flag set. Perf record already sets the flag in a similar way when there
> is more than one event, so add the same logic to evlist__new_default().
>
> evlist__new_default() is only currently used in tests, so I don't
> expect this change to have any other side effects.
>
> The session topology test has been failing on Arm big.LITTLE platforms
> since commit 251aa040244a ("perf parse-events: Wildcard most
> "numeric" events") when evlist__new_default() started opening multiple
> events for 'cycles'.
>
> Fixes: 251aa040244a ("perf parse-events: Wildcard most "numeric" events")
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
>  tools/perf/util/evlist.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 95f25e9fb994..56db37fac6f6 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -95,6 +95,7 @@ struct evlist *evlist__new_default(void)
>         struct evlist *evlist = evlist__new();
>         bool can_profile_kernel;
>         int err;
> +       struct evsel *evsel;
>
>         if (!evlist)
>                 return NULL;
> @@ -106,6 +107,10 @@ struct evlist *evlist__new_default(void)
>                 evlist = NULL;
>         }
>
> +       if (evlist->core.nr_entries > 1)
> +               evlist__for_each_entry(evlist, evsel)
> +                       evsel__set_sample_id(evsel, false);
> +

nit: the if should have curlies, with them we can reduce the scope of
evsel like below. It is also nice for constants to name the arguments
[1].

if (evlist->core.nr_entries > 1) {
    struct evsel *evsel;

    evlist__for_each_entry(evlist, evsel)
        evsel__set_sample_id(evsel, /*can_sample_identifier=*/false);
}

Tested-by: Ian Rogers <irogers@google.com>
(also Reviewed-by)

When testing with this with Mark's change [2] I see on alderlake two failures:
```
irogers@alderlake:~$ perf test 74 -vv
Couldn't bump rlimit(MEMLOCK), failures may take place when creating
BPF maps, etc
74: daemon operations                                               :
--- start ---
test child forked, pid 553821
test daemon list
test daemon reconfig
test daemon stop
test daemon signal
signal 12 sent to session 'test [554082]'
signal 12 sent to session 'test [554082]'
FAILED: perf data no generated
test daemon ping
test daemon lock
test child finished with -1
---- end ----
daemon operations: FAILED!
irogers@alderlake:~$ perf test 76 -vv
Couldn't bump rlimit(MEMLOCK), failures may take place when creating
BPF maps, etc
76: perf list tests                                                 :
--- start ---
test child forked, pid 554167
Json output test
Expecting ',' delimiter: line 4971 column 2 (char 243497)
test child finished with -1
---- end ----
perf list tests: FAILED!
```
So I think this patch may be exposing other latent issues. I'll try to
take a look.

Another thought, rather than having an evlist validate we should just
assert the evlist is always in a good shape whenever it is mutated.
That would have avoided this bug as the code would have blown up
early.

Thanks,
Ian

[1] https://clang.llvm.org/extra/clang-tidy/checks/bugprone/argument-comment.html
[2] https://lore.kernel.org/lkml/20240116170348.463479-1-mark.rutland@arm.com/

>         return evlist;
>  }


>
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 95f25e9fb994..56db37fac6f6 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -95,6 +95,7 @@  struct evlist *evlist__new_default(void)
 	struct evlist *evlist = evlist__new();
 	bool can_profile_kernel;
 	int err;
+	struct evsel *evsel;
 
 	if (!evlist)
 		return NULL;
@@ -106,6 +107,10 @@  struct evlist *evlist__new_default(void)
 		evlist = NULL;
 	}
 
+	if (evlist->core.nr_entries > 1)
+		evlist__for_each_entry(evlist, evsel)
+			evsel__set_sample_id(evsel, false);
+
 	return evlist;
 }