Messages in this thread | | | From | Ian Rogers <> | Date | Wed, 30 Nov 2022 10:58:37 -0800 | Subject | Re: [PATCH v3 5/6] perf vendor events arm64: Add PE utilization metrics for neoverse-n2 |
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On Thu, Nov 24, 2022 at 9:15 AM Jing Zhang <renyu.zj@linux.alibaba.com> wrote: > > Add PE utilization related metrics. > > Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com> > --- > .../arch/arm64/arm/neoverse-n2/metrics.json | 45 ++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json > index 23c7d62..7b54819 100644 > --- a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json > +++ b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json > @@ -189,5 +189,50 @@ > "MetricGroup": "Branch", > "MetricName": "branch_miss_pred_rate", > "ScaleUnit": "100%" > + }, > + { > + "MetricExpr": "instructions / CPU_CYCLES", > + "PublicDescription": "The average number of instructions executed for each cycle.", > + "BriefDescription": "Instructions per cycle", > + "MetricGroup": "PEutilization", > + "MetricName": "ipc" > + },
A related useful metric is percentage of peak, so if the peak IPC is 8 (usually a constant related to the number of functional units) then you can just compute the ratio of IPC with this.
> + { > + "MetricExpr": "INST_RETIRED / CPU_CYCLES", > + "PublicDescription": "Architecturally executed Instructions Per Cycle (IPC)", > + "BriefDescription": "Architecturally executed Instructions Per Cycle (IPC)",
The duplicated descriptions are unnecessary. Drop the public one for consistency with what we do for Intel: https://github.com/intel/perfmon/blob/main/scripts/create_perf_json.py#L299
> + "MetricGroup": "PEutilization", > + "MetricName": "retired_ipc" > + }, > + { > + "MetricExpr": "INST_SPEC / CPU_CYCLES", > + "PublicDescription": "Speculatively executed Instructions Per Cycle (IPC)", > + "BriefDescription": "Speculatively executed Instructions Per Cycle (IPC)", > + "MetricGroup": "PEutilization", > + "MetricName": "spec_ipc" > + }, > + { > + "MetricExpr": "OP_RETIRED / OP_SPEC", > + "PublicDescription": "Fraction of operations retired", > + "BriefDescription": "Fraction of operations retired",
Would instructions be clearer than operations here?
> + "MetricGroup": "PEutilization", > + "MetricName": "retired_rate", > + "ScaleUnit": "100%" > + }, > + { > + "MetricExpr": "1 - OP_RETIRED / OP_SPEC",
Should OP_RETIRED be greater than OP_SPEC? In which case won't this metric be negative?
> + "PublicDescription": "Fraction of operations wasted", > + "BriefDescription": "Fraction of operations wasted", > + "MetricGroup": "PEutilization", > + "MetricName": "wasted_rate", > + "ScaleUnit": "100%" > + }, > + { > + "MetricExpr": "OP_RETIRED / OP_SPEC * (1 - (STALL_SLOT - CPU_CYCLES) / (CPU_CYCLES * 5))", > + "PublicDescription": "Utilization of CPU", > + "BriefDescription": "Utilization of CPU",
Some more detail in the description would be useful.
> + "MetricGroup": "PEutilization", > + "MetricName": "cpu_utilization", > + "ScaleUnit": "100%" > } > ] > -- > 1.8.3.1 >
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