linux-kernel - Re: [PATCH 3/4] perf parse-events: Support different format of the topdown event name

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Date:   Fri, 13 May 2022 09:44:44 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     kan.liang@...ux.intel.com
Cc:     acme@...nel.org, mingo@...hat.com, jolsa@...nel.org,
        namhyung@...nel.org, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org, peterz@...radead.org,
        zhengjun.xing@...ux.intel.com, adrian.hunter@...el.com,
        ak@...ux.intel.com, eranian@...gle.com
Subject: Re: [PATCH 3/4] perf parse-events: Support different format of the
 topdown event name

On Fri, May 13, 2022 at 8:16 AM <kan.liang@...ux.intel.com> wrote:
>
> From: Kan Liang <kan.liang@...ux.intel.com>
>
> The evsel->name may have a different format for a topdown event, a pure
> topdown name (e.g., topdown-fe-bound), or a PMU name + a topdown name
> (e.g., cpu/topdown-fe-bound/). The cpu/topdown-fe-bound/ kind format
> isn't supported by the arch_evlist__leader(). This format is a very
> common format for a hybrid platform, which requires specifying the PMU
> name for each event.
>
> Without the patch,
>
> $perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1
>
>  Performance counter stats for 'system wide':
>
>      <not counted>      instructions
>      <not counted>      slots
>    <not supported>      cpu/topdown-fe-bound/
>
>        1.003482041 seconds time elapsed
>
> Some events weren't counted. Try disabling the NMI watchdog:
>         echo 0 > /proc/sys/kernel/nmi_watchdog
>         perf stat ...
>         echo 1 > /proc/sys/kernel/nmi_watchdog
> The events in group usually have to be from the same PMU. Try reorganizing the group.
>
>
> With the patch,
>
> perf stat -e '{instructions,slots,cpu/topdown-fe-bound/}' -a sleep 1
>
>  Performance counter stats for 'system wide':
>
>        157,383,996      slots
>         25,011,711      instructions
>         27,441,686      cpu/topdown-fe-bound/
>
>        1.003530890 seconds time elapsed
>
> Fixes: bc355822f0d9 ("perf parse-events: Move slots only with topdown")
> Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>

Reviewed-by: Ian Rogers <irogers@...gle.com>

Thanks,
Ian

> ---
>  tools/perf/arch/x86/util/evlist.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
> index cfc208d71f00..75564a7df15b 100644
> --- a/tools/perf/arch/x86/util/evlist.c
> +++ b/tools/perf/arch/x86/util/evlist.c
> @@ -36,7 +36,7 @@ struct evsel *arch_evlist__leader(struct list_head *list)
>                                 if (slots == first)
>                                         return first;
>                         }
> -                       if (!strncasecmp(evsel->name, "topdown", 7))
> +                       if (strcasestr(evsel->name, "topdown"))
>                                 has_topdown = true;
>                         if (slots && has_topdown)
>                                 return slots;
> --
> 2.35.1
>