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Message-ID: <a6e1114c-b37c-6999-0668-039aa495db84@linux.alibaba.com>
Date: Mon, 19 Jun 2023 16:59:08 +0800
From: Jing Zhang <renyu.zj@...ux.alibaba.com>
To: John Garry <john.g.garry@...cle.com>,
Ian Rogers <irogers@...gle.com>, Will Deacon <will@...nel.org>,
Shuai Xue <xueshuai@...ux.alibaba.com>,
Robin Murphy <robin.murphy@....com>
Cc: James Clark <james.clark@....com>,
Mike Leach <mike.leach@...aro.org>,
Leo Yan <leo.yan@...aro.org>,
Mark Rutland <mark.rutland@....com>,
Ilkka Koskinen <ilkka@...amperecomputing.com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-perf-users@...r.kernel.org,
Zhuo Song <zhuo.song@...ux.alibaba.com>
Subject: Re: [PATCH v3 2/7] perf metric: Event "Compat" value supports
matching multiple identifiers
在 2023/6/19 下午3:07, John Garry 写道:
> On 19/06/2023 03:58, Jing Zhang wrote:
>>> +++ b/tools/perf/pmu-events/arch/arm64/arm/cmn/sys/metrics.json
>>> @@ -0,0 +1,74 @@
>>> +[
>>> + {
>>> + "MetricName": "slc_miss_rate",
>>> + "BriefDescription": "The system level cache miss rate include.",
>>> + "MetricGroup": "arm_cmn",
>>> + "MetricExpr": "hnf_cache_miss / hnf_slc_sf_cache_access",
>>>
>>> So this expression uses event aliases hnf_cache_miss and hnf_slc_sf_cache_access - where are they defined in a JSON?
>>>
>> Hi John,
>>
>> I defined the aliases for these events in the JSON file during the RFC version. However, I later removed the alias
>> definitions for these events in subsequent versions due to the possibility of non-uniqueness and difficulty in defining
>> their EventCode. But this does not affect their usage in metrics. In other words, metrics can use the aliases without
>> defining event aliases in the JSON file.
>
> Really? So how can we resolve the event aliases when we try to run the metric?
>
> Please verify running these metrics with 'perf stat', like 'perf stat -v -M slc_miss_rate'
>
Ok, it shows:
#./perf stat -v -M slc_miss_rate sleep 1
metric expr hnf_cache_miss / hnf_slc_sf_cache_access for slc_miss_rate
found event duration_time
found event hnf_slc_sf_cache_access
found event hnf_cache_miss
Parsing metric events '{hnf_slc_sf_cache_access/metric-id=hnf_slc_sf_cache_access/,hnf_cache_miss/metric-id=hnf_cache_miss/}:W,duration_time'
hnf_slc_sf_cache_access -> arm_cmn_0/type=0x5,eventid=0x2/
hnf_slc_sf_cache_access -> arm_cmn_1/type=0x5,eventid=0x2/
hnf_cache_miss -> arm_cmn_0/type=0x5,eventid=0x1/
hnf_cache_miss -> arm_cmn_1/type=0x5,eventid=0x1/
Control descriptor is not initialized
hnf_slc_sf_cache_access: 127615 1001344900 1001344900
hnf_cache_miss: 36829 1001344900 1001344900
hnf_slc_sf_cache_access: 131526 1001343540 1001343540
hnf_cache_miss: 40587 1001343540 1001343540
duration_time: 1001381687 1001381687 1001381687
Performance counter stats for 'system wide':
259,141 hnf_slc_sf_cache_access # 29.9 % slc_miss_rate
77,416 hnf_cache_miss
1,001,381,687 ns duration_time
1.001381687 seconds time elapsed
#./perf list
...
arm_cmn_0/hnf_cache_miss/ [Kernel PMU event]
arm_cmn_0/hnf_slc_sf_cache_access/ [Kernel PMU event]
...
arm_cmn_1/hnf_cache_miss/ [Kernel PMU event]
arm_cmn_1/hnf_slc_sf_cache_access/ [Kernel PMU event]
...
>>
>> In the past, I always thought that the function of the alias was to explain the meaning of these events in the perf list.
>> Or maybe I'm missing something?
>
> Event aliases do give the ability to describe the event in perf list. But we can also run them for 'perf stat', like:
>
> ./perf list uncore
> List of pre-defined events (to be used in -e or -M):
>
> uncore_cbox_0/clockticks/ [Kernel PMU event]
> uncore_cbox_1/clockticks/ [Kernel PMU event]
> uncore_imc/data_reads/ [Kernel PMU event]
> uncore_imc/data_writes/ [Kernel PMU event]
> uncore_imc/gt_requests/ [Kernel PMU event]
> uncore_imc/ia_requests/ [Kernel PMU event]
> uncore_imc/io_requests/ [Kernel PMU event]
>
> uncore cache:
> unc_cbo_cache_lookup.any_es
> [L3 Lookup any request that access cache and found line in E or S-state. Unit: uncore_cbox]
> ...
>
> sudo ./perf stat -v -e unc_cbo_cache_lookup.any_es
> Using CPUID GenuineIntel-6-3D-4
> unc_cbo_cache_lookup.any_es -> uncore_cbox_0/event=0x34,umask=0x86/
> unc_cbo_cache_lookup.any_es -> uncore_cbox_1/event=0x34,umask=0x86/
> Control descriptor is not initialized
> ^Cunc_cbo_cache_lookup.any_es: 14361103 1853372468 1853372468
> unc_cbo_cache_lookup.any_es: 14322188 1853360415 1853360415
>
> Performance counter stats for 'system wide':
>
> 14,361,103 unc_cbo_cache_lookup.any_es
> 14,322,188 unc_cbo_cache_lookup.any_es
>
> 1.853388227 seconds time elapsed
>
Ok, thanks. If I use events without a prefix, such as perf stat -e clockticks sleep 1, will this also work?
Thanks,
Jing
>
> Thanks,
> John
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