[RFC,v2,0/6] Add metrics for neoverse-n2

Message

Jing Zhang Nov. 14, 2022, 7:41 a.m. UTC

Changes since v1: 
- Corrected formula for topdown L1 due to wrong counts for stall_slot and
  stall_slot_frontend; 
- Link: https://lore.kernel.org/all/[e-mail]/

This series add six metricgroups for neoverse-n2, among which, the formula of
topdown L1 is from the document:
https://documentation-service.arm.com/static/60250c7395978b529036da86?token=

Due to the wrong count of stall_slot and stall_slot_frontend in neoverse-n2, the
real stall_slot and real stall_slot_frontend need to subtract cpu_cycles, so
when calculating the topdownL1 metrics, stall_slot and stall_slot_frontend are
corrected.

Since neoverse-n2 does not yet support topdown L2, metricgroups such as Cache,
TLB, Branch, InstructionsMix, and PEutilization are added to help further
analysis of performance bottlenecks.

with this series on neoverse-n2:

$./perf list

...
Metric Groups:

Branch:
  branch_miss_pred_rate
       [The rate of branches mis-predited to the overall branches]
  branch_mpki
       [The rate of branches mis-predicted per kilo instructions]
  branch_pki
       [The rate of branches retired per kilo instructions]
Cache:
  l1d_cache_miss_rate
       [The rate of L1 D-Cache misses to the overall L1 D-Cache]
  l1d_cache_mpki
       [The rate of L1 D-Cache misses per kilo instructions]
...


$sudo ./perf stat -a -M TLB sleep 1

 Performance counter stats for 'system wide':

        35,861,936      L1I_TLB                          #     0.00 itlb_walk_rate           (74.91%)
             5,661      ITLB_WALK                                                            (74.91%)
        97,279,240      INST_RETIRED                     #     0.07 itlb_mpki                (74.91%)
             6,851      ITLB_WALK                                                            (74.91%)
            26,391      DTLB_WALK                        #     0.00 dtlb_walk_rate           (75.07%)
        35,585,545      L1D_TLB                                                              (75.07%)
        85,923,244      INST_RETIRED                     #     0.35 dtlb_mpki                (75.11%)
            29,992      DTLB_WALK                                                            (75.11%)

       1.003450755 seconds time elapsed


$sudo ./perf stat -M TopDownL1 false_sharing 2

Performance counter stats for 'false_sharing 2':

     3,388,884,713      cpu_cycles                       #     0.05 retiring
                                                  #     0.00 wasted                   (66.59%)
    19,495,064,576      stall_slot                                                           (66.59%)
       838,235,126      op_spec                                                              (66.59%)
       836,787,162      op_retired                                                           (66.59%)
     3,380,520,038      cpu_cycles                       #     0.29 frontend_bound           (67.15%)
     8,267,545,049      stall_slot_frontend                                                  (67.15%)
     3,389,138,804      cpu_cycles                       #     0.67 backend_bound            (66.66%)
    11,337,766,816      stall_slot_backend                                                   (66.66%)

       0.442572628 seconds time elapsed

       1.235153000 seconds user
       0.000000000 seconds sys

Jing Zhang (6):
  perf vendor events arm64: Add topdown L1 metrics for neoverse-n2
  perf vendor events arm64: Add TLB metrics for neoverse-n2
  perf vendor events arm64: Add cache metrics for neoverse-n2
  perf vendor events arm64: Add branch metrics for neoverse-n2
  perf vendor events arm64: Add PE utilization metrics for neoverse-n2
  perf vendor events arm64: Add instruction mix metrics for neoverse-n2

 .../arch/arm64/arm/neoverse-n2/metrics.json        | 247 +++++++++++++++++++++
 1 file changed, 247 insertions(+)
 create mode 100644 tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json