Re: [External] : [RFC PATCH v2 1/6] perf vendor events arm64: Add topdown L1 metrics for neoverse-n2

Jing Zhang
2022-11-21T15:20:31Z

在 2022/11/21 下午6:22, John Garry 写道:
>
>>
>>
>> #./perf stat -e FRONTEND_BOUND sleep 1
>> event syntax error: 'FRONTEND_BOUND'
>
> For metrics, use -M, not -e
>
> If this doesn't help, verify generated pmu-events/pmu-events.c is same after you make the change to try to use std arch events for metrics. Note that I never tested running my change.
>
> Thanks,
> John
>
>>                       \___ parser error
>> Run 'perf list' for a list of valid events
>>
>>   Usage: perf stat [<options>] [<command>]
>>
>>      -e, --event <event>   event selector. use 'perf list' to list available events
>>
>>
>>
>> diff --git a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/pipeline.json b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/pipeli
>> index f9fae15..1089ca0 100644
>> --- a/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/pipeline.json
>> +++ b/tools/perf/pmu-events/arch/arm64/arm/neoverse-n2/pipeline.json
>> @@ -6,18 +6,24 @@
>>           "ArchStdEvent": "STALL_BACKEND"
>>       },
>>       {
>> -        "ArchStdEvent": "STALL_SLOT_FRONTEND"
>> +        "ArchStdEvent": "STALL_SLOT_FRONTEND",
>> +        "MetricExpr": "STALL_SLOT_FRONTEND - CPU_CYCLES"
>>       },
>>       {
>>

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"
+ },
+ {
+ "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?

Looking forward to your reply.

Thanks,
Jing