mbox series

[v8,0/8] Add support for Sub-NUMA cluster (SNC) systems

Message ID 20231003213043.13565-1-tony.luck@intel.com
Headers
Series Add support for Sub-NUMA cluster (SNC) systems |

Message

Luck, Tony Oct. 3, 2023, 9:30 p.m. UTC 
  The Sub-NUMA cluster feature on some Intel processors partitions
the CPUs that share an L3 cache into two or more sets. This plays
havoc with the Resource Director Technology (RDT) monitoring features.
Prior to this patch Intel has advised that SNC and RDT are incompatible.

Some of these CPU support an MSR that can partition the RMID
counters in the same way. This allows for monitoring features
to be used (with the caveat that memory accesses between different
SNC NUMA nodes may still not be counted accurately.

Note that this patch series improves resctrl reporting considerably
on systems with SNC enabled, but there will still be some anomalies
for processes accessing memory from other sub-NUMA nodes.

Signed-off-by: Tony Luck <tony.luck@intel.com>

---
Please ignore v7 posting. There was some glitch in how I created
the patches with "git format-patch" that meant part 0004 would not
apply.

Changes since v6:

* Fixed spelling of "accurately" in cover letter.

* Applied changes from Peter Newman's review
Link: https://lore.kernel.org/r/CALPaoChB5ryT96ZZBQb6+3=xO+A0uR-ToN0TWqUjLJ7bgi==Rg@mail.gmail.com
(and follow-on posts against other patches in the v6 series).

See comments in indivdual patches for specific details.

Added Peter's "Reviewed-by" to parts 4-7.q

Tony Luck (8):
  x86/resctrl: Prepare for new domain scope
  x86/resctrl: Prepare to split rdt_domain structure
  x86/resctrl: Prepare for different scope for control/monitor
    operations
  x86/resctrl: Split the rdt_domain and rdt_hw_domain structures
  x86/resctrl: Add node-scope to the options for feature scope
  x86/resctrl: Introduce snc_nodes_per_l3_cache
  x86/resctrl: Sub NUMA Cluster detection and enable
  x86/resctrl: Update documentation with Sub-NUMA cluster changes

 Documentation/arch/x86/resctrl.rst        |  23 +-
 include/linux/resctrl.h                   |  85 +++--
 arch/x86/include/asm/msr-index.h          |   1 +
 arch/x86/kernel/cpu/resctrl/internal.h    |  66 ++--
 arch/x86/kernel/cpu/resctrl/core.c        | 400 +++++++++++++++++-----
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c |  58 ++--
 arch/x86/kernel/cpu/resctrl/monitor.c     |  58 ++--
 arch/x86/kernel/cpu/resctrl/pseudo_lock.c |  14 +-
 arch/x86/kernel/cpu/resctrl/rdtgroup.c    | 132 +++----
 9 files changed, 591 insertions(+), 246 deletions(-)


base-commit: 6465e260f48790807eef06b583b38ca9789b6072

Comments

Reinette Chatre Oct. 3, 2023, 9:44 p.m. UTC | #1 
Tony,

On 10/3/2023 2:30 PM, Tony Luck wrote:
> The Sub-NUMA cluster feature on some Intel processors partitions
> the CPUs that share an L3 cache into two or more sets. This plays
> havoc with the Resource Director Technology (RDT) monitoring features.
> Prior to this patch Intel has advised that SNC and RDT are incompatible.
> 
> Some of these CPU support an MSR that can partition the RMID
> counters in the same way. This allows for monitoring features
> to be used (with the caveat that memory accesses between different
> SNC NUMA nodes may still not be counted accurately.

Almost. For reference:
https://lore.kernel.org/lkml/e350514e-76ed-14ea-3e74-c0852658182f@intel.com/

No need to send a new series just for this, but this series does find
itself at the back of my queue.

> Note that this patch series improves resctrl reporting considerably
> on systems with SNC enabled, but there will still be some anomalies
> for processes accessing memory from other sub-NUMA nodes.
> 
> Signed-off-by: Tony Luck <tony.luck@intel.com>

Reinette
Shaopeng Tan (Fujitsu) Oct. 5, 2023, 8:10 a.m. UTC | #2 
Hi Tony,

I applied this patch series to kernel v6.5 and v6.6-rc4, but the kernel cannot be booted.
Could you tell me what kernel version this patch series is based on?

Best regards,
Shaopeng TAN
Luck, Tony Oct. 5, 2023, 3:08 p.m. UTC | #3 
> I applied this patch series to kernel v6.5 and v6.6-rc4, but the kernel cannot be booted.
> Could you tell me what kernel version this patch series is based on?

Hi Shaopeng,

Patches are based on v6.6-rc3 (see the "base-commit" line at the end of the cover letter).

Which CPU family/model/stepping & microcode are you testing on?

Are there error or panic messages when it does not boot?

-Tony
Reinette Chatre Oct. 6, 2023, 8:27 p.m. UTC | #4 
Hi Tony,

On 10/5/2023 8:08 AM, Luck, Tony wrote:
>> I applied this patch series to kernel v6.5 and v6.6-rc4, but the kernel cannot be booted.
>> Could you tell me what kernel version this patch series is based on?
> 
> Hi Shaopeng,
> 
> Patches are based on v6.6-rc3 (see the "base-commit" line at the end of the cover letter).
> 
> Which CPU family/model/stepping & microcode are you testing on?
> 
> Are there error or panic messages when it does not boot?

There is no need to ask Shaopeng for more information. If you test
this series you will immediately learn that it is broken. 
Reading the series I only made it to patch #3 where I realized that this
has not been tested before posting. 

Reinette