From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
Chun-Tse Shao <ctshao@google.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v1] perf stat display: Make %f precision consistent
Date: Mon, 12 Jan 2026 15:56:19 -0300 [thread overview]
Message-ID: <aWVD0zctSqflXKdU@x1> (raw)
In-Reply-To: <CAP-5=fVf=Db9+9gxmfoRPDZvp_jz3bwG9FqLwAnKVHjaHbe4MQ@mail.gmail.com>
On Thu, Jan 08, 2026 at 11:25:17AM -0800, Ian Rogers wrote:
> On Tue, Dec 9, 2025 at 9:45 AM Ingo Molnar <mingo@kernel.org> wrote:
> >
> > * Ian Rogers <irogers@google.com> wrote:
> >
> > > Commit bc22de9bcdb2 ("perf stat: Display time in precision based on
> > > std deviation") added multirun workload elapsed time. There was an
> > > effort to make the precision in the output most useful for the user,
> > > however, when gathering over runs it means the formatting varies. This
> > > change just makes the output format fixed.
> > >
> > > Before:
> > > ```
> > > $ while :; do perf stat --null --repeat 3 sleep 0.1 2>&1 | grep elapsed; done
> > > 0.101140 +- 0.000149 seconds time elapsed ( +- 0.15% )
> > > 0.1011396 +- 0.0000218 seconds time elapsed ( +- 0.02% )
> > > 0.101331 +- 0.000124 seconds time elapsed ( +- 0.12% )
> > > ^C
> > > $ while :; do perf stat --null --repeat 3 sleep 1 2>&1 | grep elapsed; done
> > > 1.001317 +- 0.000146 seconds time elapsed ( +- 0.01% )
> > > 1.001377 +- 0.000172 seconds time elapsed ( +- 0.02% )
> > > 1.00253 +- 0.00131 seconds time elapsed ( +- 0.13% )
> > > ```
> > >
> > > After:
> > > ```
> > > $ while :; do perf stat --null --repeat 3 sleep 0.1 2>&1 | grep elapsed; done
> > > 0.101406408 +- 0.000064778 seconds time elapsed ( +- 0.06% )
> > > 0.101367315 +- 0.000027253 seconds time elapsed ( +- 0.03% )
> > > 0.101434164 +- 0.000084750 seconds time elapsed ( +- 0.08% )
> > > ^C
> > > $ while :; do perf stat --null --repeat 3 sleep 1 2>&1 | grep elapsed; done
> > > 1.001525467 +- 0.000051703 seconds time elapsed ( +- 0.01% )
> > > 1.001375093 +- 0.000116200 seconds time elapsed ( +- 0.01% )
> > > 1.001141025 +- 0.000046361 seconds time elapsed ( +- 0.00% )
> >
> > Perfect, thank you!
> >
> > Tested-by: Ingo Molnar <mingo@kernel.org>
>
> Ping.
Thanks, applied to perf-tools-next,
- Arnaldo
prev parent reply other threads:[~2026-01-12 18:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-09 17:36 [PATCH v1] perf stat display: Make %f precision consistent Ian Rogers
2025-12-09 17:45 ` Ingo Molnar
2026-01-08 19:25 ` Ian Rogers
2026-01-12 18:56 ` Arnaldo Carvalho de Melo [this message]
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