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Date:   Mon, 21 Nov 2022 23:17:11 +0800
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Subject: Re: [External] : [RFC PATCH v2 1/6] perf vendor events arm64: Add
 topdown L1 metrics for neoverse-n2
To:     John Garry <john.g.garry@oracle.com>,
        linux-arm-kernel@lists.infradead.org,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        John Garry <john.garry@huawei.com>,
        Will Deacon <will@kernel.org>,
        James Clark <james.clark@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>, Ian Rogers <irogers@google.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Andrew Kilroy <andrew.kilroy@arm.com>,
        Shuai Xue <xueshuai@linux.alibaba.com>,
        Zhuo Song <zhuo.song@linux.alibaba.com>
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From:   Jing Zhang <renyu.zj@linux.alibaba.com>
In-Reply-To: <abebb42b-62c1-30d7-ad9a-5fbf6c0edce1@oracle.com>
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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