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From: Ian Rogers <irogers@google.com>
Date: Wed, 5 Jun 2024 10:21:10 -0700
Message-ID: <CAP-5=fV+-ytA2st17Ar-jQ5xYqrWtxnF2TcADKrC5WoPyKz4wQ@mail.gmail.com>
Subject: Re: [PATCH] perf stat: Fix the hard-coded metrics calculation on the hybrid
To: kan.liang@linux.intel.com
Cc: acme@kernel.org, namhyung@kernel.org, jolsa@kernel.org, 
	adrian.hunter@intel.com, linux-perf-users@vger.kernel.org, 
	linux-kernel@vger.kernel.org, "Khalil, Amiri" <amiri.khalil@intel.com>, 
	stable@vger.kernel.org
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On Wed, Jun 5, 2024 at 9:10=E2=80=AFAM <kan.liang@linux.intel.com> wrote:
>
> From: Kan Liang <kan.liang@linux.intel.com>
>
> The hard-coded metrics is wrongly calculated on the hybrid machine.
>
> $ perf stat -e cycles,instructions -a sleep 1
>
>  Performance counter stats for 'system wide':
>
>         18,205,487      cpu_atom/cycles/
>          9,733,603      cpu_core/cycles/
>          9,423,111      cpu_atom/instructions/     #  0.52  insn per cycl=
e
>          4,268,965      cpu_core/instructions/     #  0.23  insn per cycl=
e
>
> The insn per cycle for cpu_core should be 4,268,965 / 9,733,603 =3D 0.44.
>
> When finding the metric events, the find_stat() doesn't take the PMU
> type into account. The cpu_atom/cycles/ is wrongly used to calculate
> the IPC of the cpu_core.
>
> Fixes: 0a57b910807a ("perf stat: Use counts rather than saved_value")
> Reported-by: "Khalil, Amiri" <amiri.khalil@intel.com>
> Signed-off-by: Kan Liang <kan.liang@linux.intel.com>

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

Thanks,
Ian

> Cc: stable@vger.kernel.org
> ---
>  tools/perf/util/stat-shadow.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.=
c
> index 3466aa952442..4d0edc061f1a 100644
> --- a/tools/perf/util/stat-shadow.c
> +++ b/tools/perf/util/stat-shadow.c
> @@ -176,6 +176,10 @@ static double find_stat(const struct evsel *evsel, i=
nt aggr_idx, enum stat_type
>                 if (type !=3D evsel__stat_type(cur))
>                         continue;
>
> +               /* Ignore if not the PMU we're looking for. */
> +               if (evsel->pmu !=3D cur->pmu)
> +                       continue;
> +
>                 aggr =3D &cur->stats->aggr[aggr_idx];
>                 if (type =3D=3D STAT_NSECS)
>                         return aggr->counts.val;
> --
> 2.35.1
>