Messages in this thread | | | Date | Tue, 22 Nov 2022 17:24:59 +0800 | Subject | Re: [External] : [RFC PATCH v2 1/6] perf vendor events arm64: Add topdown L1 metrics for neoverse-n2 | From | Jing Zhang <> |
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在 2022/11/22 上午1:55, John Garry 写道: > On 21/11/2022 15:17, Jing Zhang wrote: >> I'm sorry that I misunderstood the purpose of putting metric as arch_std_event at first, >> and now it works after the modification over your suggestion. >> >> But there are also a few questions: >> >> 1. The value of the slot in the topdownL1 is various in different architectures, for example, >> the slot is 5 on neoverse-n2. If I put topdownL1 metric as arch_std_event, then I need to >> specify the slot to 5 in n2. I can specify slot values in metric like below, but is there any >> other concise way to do this? >> >> 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 8ff1dfe..b473baf 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 >> @@ -1,4 +1,23 @@ >> [ >> + { >> + "MetricExpr": "5", >> + "PublicDescription": "A pipeline slot represents the hardware resources needed to process one uOp", >> + "BriefDescription": "A pipeline slot represents the hardware resources needed to process one uOp", >> + "MetricName": "slot" > > Ehhh....I'm not sure if that is a good idea. Ian or anyone else have an opinion on this? It is possible to reuse metrics, so it should work, but... > > One problem is that "slot" would show up as a metric, which you would not want. > > Alternatively I was going to suggest that you can overwrite specific std arch event attributes. So for example of frontend_bound, you could have: > > + b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/metrics.json > @@ -0,0 +1,30 @@ > [ > { > "ArchStdEvent": "FRONTEND_BOUND", > "MetricExpr": "(stall_slot_frontend - cpu_cycles) / (5 * cpu_cycles)", > }, > >> + } >> + { >> + "ArchStdEvent": "FRONTEND_BOUND" >> + }, >> + { >> + "ArchStdEvent": "BACKEND_BOUND" >> + }, >> + { >> + "ArchStdEvent": "WASTED" >> + }, >> + { >> + "ArchStdEvent": "RETIRING" >> + }, >> >> >> 2. Should I add the topdownL1 metric to tools/perf/pmu-event/recommended.json, >> or create a new json file to place the general metric? > > It would not belong in recommended.json as that is specifically for arch-recommended events. It would really just depend on where the value comes from, i.e. arm arm or sbsa. >
Thanks for your suggestion, I will send next patchset as you suggested.
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