[PATCH 0/6] perf/x86/amd: Add memory controller events

[Sandipan Das]

Unified Memory Controller (UMC) events were introduced with Zen 4 as a
part of the Performance Monitoring Version 2 (PerfMonV2) enhancements.
Currently, Zen 4 supports upto 12 channels of DDR5 memory and each of
them are controlled by a dedicated UMC. Each UMC, in turn, has its own
set of performance monitoring counters. These counters can provide info
on UMC command activity which in turn can be used to derive utilization
and bandwidth. Using perf tool, users can profile activity either on a
combined basis (includes all active UMCs) or for individual UMCs.

E.g. measurement across all UMCs

  $ sudo perf stat -e amd_umc/umc_cas_cmd.all/ -a -- sleep 1

   Performance counter stats for 'system wide':

             544,810      amd_umc/umc_cas_cmd.all/

         1.002012663 seconds time elapsed

E.g. measurement specific to certain UMCs

  $ sudo perf stat -e amd_umc_0/umc_cas_cmd.all/ -e amd_umc_6/umc_cas_cmd.all/ -a -- sleep 1

   Performance counter stats for 'system wide':

              21,096      amd_umc_0/umc_cas_cmd.all/
              35,428      amd_umc_6/umc_cas_cmd.all/

         1.001802611 seconds time elapsed

The available UMCs can be found from sysfs and the socket to which they
belong can be derived from the cpumask.

E.g.

  $ find /sys/devices/ -maxdepth 1 -name "amd_umc_*"

  /sys/devices/amd_umc_9
  /sys/devices/amd_umc_7
  /sys/devices/amd_umc_5
  /sys/devices/amd_umc_3
  /sys/devices/amd_umc_1
  /sys/devices/amd_umc_10
  /sys/devices/amd_umc_8
  /sys/devices/amd_umc_6
  /sys/devices/amd_umc_4
  /sys/devices/amd_umc_2
  /sys/devices/amd_umc_11
  /sys/devices/amd_umc_0

  $ cat /sys/devices/amd_umc_0/cpumask
  0

  $ cat /sys/devices/amd_umc_6/cpumask
  96

All of the output above comes from a dual socket Genoa system having
96 cores and 6 populated memory channels per socket.

Sandipan Das (6):
  perf/x86/amd/uncore: Refactor uncore management
  perf/x86/amd/uncore: Use rdmsr if rdpmc is unavailable
  x86/cpuid: Add smp helper
  perf/x86/amd/uncore: Add group exclusivity
  perf/x86/amd/uncore: Add memory controller support
  perf vendor events amd: Add Zen 4 memory controller events

 arch/x86/events/amd/uncore.c                  | 893 +++++++++++-------
 arch/x86/include/asm/cpuid.h                  |  14 +
 arch/x86/include/asm/msr-index.h              |   4 +
 arch/x86/include/asm/perf_event.h             |   9 +
 arch/x86/lib/Makefile                         |   2 +-
 arch/x86/lib/cpuid-smp.c                      |  36 +
 .../arch/x86/amdzen4/memory-controller.json   | 101 ++
 .../arch/x86/amdzen4/recommended.json         |  84 ++
 tools/perf/pmu-events/jevents.py              |   2 +
 9 files changed, 807 insertions(+), 338 deletions(-)
 create mode 100644 arch/x86/lib/cpuid-smp.c
 create mode 100644 tools/perf/pmu-events/arch/x86/amdzen4/memory-controller.json

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2.34.1