linux-kernel - Re: [RFC PATCH v12 6/8] perf stat: Add command line option for enabling tpebs recording

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Date: Tue, 11 Jun 2024 09:49:57 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: weilin.wang@...el.com
Cc: Ian Rogers <irogers@...gle.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, 
	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Perry Taylor <perry.taylor@...el.com>, Samantha Alt <samantha.alt@...el.com>, 
	Caleb Biggers <caleb.biggers@...el.com>
Subject: Re: [RFC PATCH v12 6/8] perf stat: Add command line option for
 enabling tpebs recording

Hello,

On Mon, Jun 10, 2024 at 10:24 PM <weilin.wang@...el.com> wrote:
>
> From: Weilin Wang <weilin.wang@...el.com>
>
> With this command line option, tpebs recording is turned off in perf stat on
> default. It will only be turned on when this option is given in perf stat
> command.
>
> Exampe with --enable-tpebs-recording:
>
> perf stat -M tma_dtlb_store -a --enable-tpebs-recording sleep 1
>
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.000 MB - ]
>
>  Performance counter stats for 'system wide':
>
>        181,047,168      cpu_core/TOPDOWN.SLOTS/          #      0.6 %  tma_dtlb_store
>          3,195,608      cpu_core/topdown-retiring/
>         40,156,649      cpu_core/topdown-mem-bound/
>          3,550,925      cpu_core/topdown-bad-spec/
>        117,571,818      cpu_core/topdown-fe-bound/
>         57,118,087      cpu_core/topdown-be-bound/
>             69,179      cpu_core/EXE_ACTIVITY.BOUND_ON_STORES/
>              4,582      cpu_core/MEM_INST_RETIRED.STLB_HIT_STORES/
>         30,183,104      cpu_core/CPU_CLK_UNHALTED.DISTRIBUTED/
>         30,556,790      cpu_core/CPU_CLK_UNHALTED.THREAD/
>            168,486      cpu_core/DTLB_STORE_MISSES.WALK_ACTIVE/
>                  0      MEM_INST_RETIRED.STLB_HIT_STORES:R

Here I guess we can expect a non-zero value, right?

>
>        1.003105924 seconds time elapsed
>
> Exampe without --enable-tpebs-recording:
>
> perf stat -M tma_dtlb_store -a sleep 1
>
>  Performance counter stats for 'system wide':
>
>        181,047,168      cpu_core/TOPDOWN.SLOTS/          #      0.6 %  tma_dtlb_store
>          3,195,608      cpu_core/topdown-retiring/
>         40,156,649      cpu_core/topdown-mem-bound/
>          3,550,925      cpu_core/topdown-bad-spec/
>        117,571,818      cpu_core/topdown-fe-bound/
>         57,118,087      cpu_core/topdown-be-bound/
>             69,179      cpu_core/EXE_ACTIVITY.BOUND_ON_STORES/
>              4,582      cpu_core/MEM_INST_RETIRED.STLB_HIT_STORES/
>         30,183,104      cpu_core/CPU_CLK_UNHALTED.DISTRIBUTED/
>         30,556,790      cpu_core/CPU_CLK_UNHALTED.THREAD/
>            168,486      cpu_core/DTLB_STORE_MISSES.WALK_ACTIVE/
>                  0      MEM_INST_RETIRED.STLB_HIT_STORES:R
>
>        1.003105924 seconds time elapsed
>
> Signed-off-by: Weilin Wang <weilin.wang@...el.com>
> ---
>  tools/perf/builtin-stat.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 14be132f7b6f..055139e44763 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -1235,6 +1235,8 @@ static struct option stat_options[] = {

What's the base of your patchset?  I think we moved this to cmd_stat().
Please make sure to rebase on the perf-tools-next.


>                        "disable adding events for the metric threshold calculation"),
>         OPT_BOOLEAN(0, "topdown", &topdown_run,
>                         "measure top-down statistics"),
> +       OPT_BOOLEAN(0, "enable-tpebs-recording", &tpebs_recording,
> +                       "enable recording for tpebs when retire_latency required"),

Please update the documentation (man page) for this option.

Also I'm afraid it'd fail to build on non-x86 because tpebes_recording
is defined in intel-tpebs.c.

Thanks,
Namhyung


>         OPT_UINTEGER(0, "td-level", &stat_config.topdown_level,
>                         "Set the metrics level for the top-down statistics (0: max level)"),
>         OPT_BOOLEAN(0, "smi-cost", &smi_cost,
> --
> 2.43.0
>