[PATCH v3 0/6] Add metrics for neoverse-n2

Jing Zhang
2022-11-24T17:15:05Z

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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@linux.alibaba.com/

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@linux.alibaba.com/

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 '/home/yaoxing/beetest/beecases/beeusers/spe/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 '/home/yaoxing/beetest/beecases/beeusers/spe/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 | 310 +++++++++++++++++++++
1 file changed, 310 insertions(+)
create mode 100644 tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json

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