[PATCH v4 0/6] Add metrics for neoverse-n2

[Jing Zhang]

Changes since v3:
- Add ipc_rate metric;
- Drop the PublicDescription;
- Describe PEutilization metrics in more detail;
- Link: https://lore.kernel.org/all/1669310088-13482-1-git-send-email-renyu.zj@xxxxxxxxxxxxxxxxx/

Changes since v2:
- Correct the furmula of Branch metrics;
- Add more PE utilization metrics;
- Add more TLB metrics;
- Add “ScaleUnit” for some metrics;
- Add a newline at the end of the file;
- Link: https://lore.kernel.org/all/1668411720-3581-1-git-send-email-renyu.zj@xxxxxxxxxxxxxxxxx/

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/1667214694-89839-1-git-send-email-renyu.zj@xxxxxxxxxxxxxxxxx/


This series add six metricgroups for neoverse-n2, among which, the formula of
topdown L1 is from ARM sbsa7.0 platform design document [0], D37-38.

However, due to the wrong count of stall_slot and stall_slot_frontend on
neoverse-n2, the real stall_slot and real stall_slot_frontend need to
subtract cpu_cycles,  so correct the expression of topdown metrics.
Reference from ARM neoverse-n2 errata notice [1], D117.

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. Reference from ARM PMU guide [2][3].

[0] https://documentation-service.arm.com/static/60250c7395978b529036da86?token=
[1] https://documentation-service.arm.com/static/636a66a64e6cf12278ad89cb?token=
[2] https://documentation-service.arm.com/static/628f8fa3dfaf015c2b76eae8?token=
[3] https://documentation-service.arm.com/static/62cfe21e31ea212bb6627393?token=


$./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 -M TLB false_sharing 2

 Performance counter stats for 'false_sharing 2':

            31,561      L2D_TLB                          #     18.8 %  l2_tlb_miss_rate      (43.23%)
             5,944      L2D_TLB_REFILL                                                       (43.23%)
             2,248      L1I_TLB_REFILL                   #      0.1 %  l1i_tlb_miss_rate     (43.85%)
         2,203,195      L1I_TLB                                                              (43.85%)
       328,647,380      L1D_TLB                          #      0.0 %  l1d_tlb_miss_rate     (44.32%)
            26,347      L1D_TLB_REFILL                                                       (44.32%)
           747,319      L1I_TLB                          #      0.0 %  itlb_walk_rate        (43.74%)
               310      ITLB_WALK                                                            (43.74%)
       839,420,454      INST_RETIRED                     #     0.00 itlb_mpki                (42.77%)
               212      ITLB_WALK                                                            (42.77%)
               468      DTLB_WALK                        #      0.0 %  dtlb_walk_rate        (42.28%)
       265,405,802      L1D_TLB                                                              (42.28%)
       790,874,367      INST_RETIRED                     #     0.00 dtlb_mpki                (42.33%)
                23      DTLB_WALK                                                            (42.33%)

       0.515904553 seconds time elapsed

       1.410313000 seconds user
       0.000000000 seconds sys


$sudo ./perf stat -M TopDownL1 false_sharing 2

 Performance counter stats for 'false_sharing 2':

     4,310,905,590      cpu_cycles                       #      0.0 %  bad_speculation
                                                  #      4.0 %  retiring              (66.87%)
    25,009,763,735      stall_slot                                                           (66.87%)
       855,659,327      op_spec                                                              (66.87%)
       854,335,288      op_retired                                                           (66.87%)
     4,330,308,058      cpu_cycles                       #     27.1 %  frontend_bound        (66.99%)
    10,207,186,460      stall_slot_frontend                                                  (66.99%)
     4,316,583,673      cpu_cycles                       #     69.4 %  backend_bound         (66.65%)
    14,979,136,808      stall_slot_backend                                                   (66.65%)

       0.572056818 seconds time elapsed

       1.572143000 seconds user
       0.004010000 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        | 277 +++++++++++++++++++++
 1 file changed, 277 insertions(+)
 create mode 100644 tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json

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1.8.3.1