linux-kernel - Re: [PATCH v4 03/48] perf stat: Correct aggregation CPU map

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Message-ID: <1ae917ec-4d32-4ee7-0948-f91eb3bf35fb@huawei.com>
Date:   Mon, 10 Jan 2022 18:43:08 +0000
From:   John Garry <john.garry@...wei.com>
To:     Ian Rogers <irogers@...gle.com>, Andi Kleen <ak@...ux.intel.com>,
        "Jiri Olsa" <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Kajol Jain <kjain@...ux.ibm.com>,
        "Paul A . Clarke" <pc@...ibm.com>,
        "Arnaldo Carvalho de Melo" <acme@...nel.org>,
        Riccardo Mancini <rickyman7@...il.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Ingo Molnar" <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        "Alexander Shishkin" <alexander.shishkin@...ux.intel.com>,
        <linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Vineet Singh" <vineet.singh@...el.com>,
        James Clark <james.clark@....com>,
        "Mathieu Poirier" <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mike Leach <mike.leach@...aro.org>,
        Leo Yan <leo.yan@...aro.org>, <coresight@...ts.linaro.org>,
        <linux-arm-kernel@...ts.infradead.org>, <zhengjun.xing@...el.com>
CC:     <eranian@...gle.com>
Subject: Re: [PATCH v4 03/48] perf stat: Correct aggregation CPU map

On 05/01/2022 06:13, Ian Rogers wrote:
> Switch the perf_cpu_map in aggr_update_shadow from
> the evlist to the counter's cpu map, so the index is appropriate. This
> addresses a problem where uncore counts, with a cpumap like:
> $ cat /sys/devices/uncore_imc_0/cpumask
> 0,18
> Don't aggregate counts in CPUs based on the index of those values in the
> cpumap (0 and 1) but on the actual CPU (0 and 18). Thereby correcting
> metric calculations in per-socket mode for counters without a full
> cpumask.
> 
> On a SkylakeX with a tweaked DRAM_BW_Use metric, to remove unnecessary
> scaling, this gives:
> 
> Before:
> $ /perf stat --per-socket -M DRAM_BW_Use -I 1000
>       1.001102293 S0        1              27.01 MiB  uncore_imc/cas_count_write/ #   103.00 DRAM_BW_Use
>       1.001102293 S0        1              30.22 MiB  uncore_imc/cas_count_read/
>       1.001102293 S0        1      1,001,102,293 ns   duration_time
>       1.001102293 S1        1              20.10 MiB  uncore_imc/cas_count_write/ #     0.00 DRAM_BW_Use
>       1.001102293 S1        1              32.74 MiB  uncore_imc/cas_count_read/
>       1.001102293 S1        0      <not counted> ns   duration_time
>       2.003517973 S0        1              83.04 MiB  uncore_imc/cas_count_write/ #   920.00 DRAM_BW_Use
>       2.003517973 S0        1             145.95 MiB  uncore_imc/cas_count_read/
>       2.003517973 S0        1      1,002,415,680 ns   duration_time
>       2.003517973 S1        1             302.45 MiB  uncore_imc/cas_count_write/ #     0.00 DRAM_BW_Use
>       2.003517973 S1        1             290.99 MiB  uncore_imc/cas_count_read/
>       2.003517973 S1        0      <not counted> ns   duration_time
> 
> After:
> $ perf stat --per-socket -M DRAM_BW_Use -I 1000
>       1.001080840 S0        1              24.96 MiB  uncore_imc/cas_count_write/ #    54.00 DRAM_BW_Use
>       1.001080840 S0        1              33.64 MiB  uncore_imc/cas_count_read/
>       1.001080840 S0        1      1,001,080,840 ns   duration_time
>       1.001080840 S1        1              42.43 MiB  uncore_imc/cas_count_write/ #    84.00 DRAM_BW_Use
>       1.001080840 S1        1              47.05 MiB  uncore_imc/cas_count_read/
>       1.001080840 S1        0      <not counted> ns   duration_time
> 
> Signed-off-by: Ian Rogers<irogers@...gle.com>

Tested-by: John Garry <john.garry@...wei.com>