[v6,5/6] perf vendor events arm64: Update stall_slot workaround for N2 r0p3

Commit Message

James Clark Aug. 16, 2023, 11:47 a.m. UTC

N2 r0p3 doesn't require the workaround [1], so gating on (#slots - 5) no
longer works because all N2s have 5 slots. Use the new expression
builtin that allows calling strcmp_cpuid_str() and comparing CPUIDs in
metric formulas.

In this case, the commented formula looks like this:

  strcmp_cpuid_str(0x410fd493)        # greater than or equal to N2 r0p3
  | strcmp_cpuid_str(0x410fd490) ^ 1  # OR NOT any version of N2

[1]: https://gitlab.arm.com/telemetry-solution/telemetry-solution/-/blob/main/data/pmu/cpu/neoverse/neoverse-n2-r0p3.json
Signed-off-by: James Clark <[e-mail]>
---
 .../pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Comments

John Garry Aug. 17, 2023, 11:08 a.m. UTC | #1

On 16/08/2023 12:47, James Clark wrote:
> N2 r0p3 doesn't require the workaround [1], so gating on (#slots - 5) no
> longer works because all N2s have 5 slots. Use the new expression
> builtin that allows calling strcmp_cpuid_str() and comparing CPUIDs in
> metric formulas.
> 
> In this case, the commented formula looks like this:
> 
>    strcmp_cpuid_str(0x410fd493)        # greater than or equal to N2 r0p3
>    | strcmp_cpuid_str(0x410fd490) ^ 1  # OR NOT any version of N2
> 
> [1]:https://urldefense.com/v3/__https://gitlab.arm.com/telemetry-solution/telemetry-solution/-/blob/main/data/pmu/cpu/neoverse/neoverse-n2-r0p3.json__;!!ACWV5N9M2RV99hQ!JvpXOAN-7zsKcA750zS-vMlcJKvvIZ_H9zg6jitWJRMitlFGDrx8bXoMrhdK5ubhO8CtXObRFx7bDYM2R5Feqg$  
> Signed-off-by: James Clark<[e-mail]>
> ---

Reviewed-by: John Garry <[e-mail]>

Patch

diff --git a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json
index 8ad15b726dca..9757cc178bdf 100644
--- a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json
+++ b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2-v2/metrics.json
@@ -1,15 +1,15 @@ 
 [
     {
         "ArchStdEvent": "FRONTEND_BOUND",
-        "MetricExpr": "((stall_slot_frontend) if (#slots - 5) else (stall_slot_frontend - cpu_cycles)) / (#slots * cpu_cycles)"
+        "MetricExpr": "((stall_slot_frontend) if (strcmp_cpuid_str(0x410fd493) | strcmp_cpuid_str(0x410fd490) ^ 1) else (stall_slot_frontend - cpu_cycles)) / (#slots * cpu_cycles)"
     },
     {
         "ArchStdEvent": "BAD_SPECULATION",
-        "MetricExpr": "(1 - op_retired / op_spec) * (1 - (stall_slot if (#slots - 5) else (stall_slot - cpu_cycles)) / (#slots * cpu_cycles))"
+        "MetricExpr": "(1 - op_retired / op_spec) * (1 - (stall_slot if (strcmp_cpuid_str(0x410fd493) | strcmp_cpuid_str(0x410fd490) ^ 1) else (stall_slot - cpu_cycles)) / (#slots * cpu_cycles))"
     },
     {
         "ArchStdEvent": "RETIRING",
-        "MetricExpr": "(op_retired / op_spec) * (1 - (stall_slot if (#slots - 5) else (stall_slot - cpu_cycles)) / (#slots * cpu_cycles))"
+        "MetricExpr": "(op_retired / op_spec) * (1 - (stall_slot if (strcmp_cpuid_str(0x410fd493) | strcmp_cpuid_str(0x410fd490) ^ 1) else (stall_slot - cpu_cycles)) / (#slots * cpu_cycles))"
     },
     {
         "ArchStdEvent": "BACKEND_BOUND"
@@ -201,7 +201,7 @@ 
         "ScaleUnit": "100%"
     },
     {
-        "MetricExpr": "OP_RETIRED / OP_SPEC * (1 - (STALL_SLOT if (#slots - 5) else (STALL_SLOT - CPU_CYCLES)) / (#slots * CPU_CYCLES))",
+        "MetricExpr": "OP_RETIRED / OP_SPEC * (1 - (STALL_SLOT if (strcmp_cpuid_str(0x410fd493) | strcmp_cpuid_str(0x410fd490) ^ 1) else (STALL_SLOT - CPU_CYCLES)) / (#slots * CPU_CYCLES))",
         "BriefDescription": "The truly effective ratio of micro-operations executed by the CPU, which means that misprediction and stall are not included",
         "MetricGroup": "PEutilization",
         "MetricName": "cpu_utilization",