Re: [PATCH] perf bench: flush stats when pipe it to a file or to tee

Arnaldo Carvalho de Melo
2021-11-13T12:18:27Z

Em Sat, Nov 13, 2021 at 09:16:42AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Nov 12, 2021 at 11:53:12PM +0200, Sohaib Mohamed escreveu:
> > The output of perf bench gets buffered when I pipe it to a file or to
> > tee, in such a way that I can see it only at the end.
>
> Good, now try with 'perf test' :-)
>
> Applying,

Humm, take that back, when I almost did it for 'perf test' I used
setvbuf(), take a look at it so that you don't have to go sprinkling
fflush() calls and missing some places.

- Arnaldo

> - Arnaldo
>
> > E.g.
> > $ perf bench internals synthesize -t
> > < output comes out fine after each test run >
> >
> > $ perf bench internals synthesize -t | tee file.txt
> > < output comes out only at the end of all tests >
> >
> > See, also:
> > $ perf bench mem all | tee file.txt
> > $ perf bench sched all | tee file.txt
> > $ perf bench internals all -t | tee file.txt
> > $ perf bench internals all | tee file.txt
> >
> > Suggested-by: Riccardo Mancini <rickyman7@gmail.com>
> > Signed-off-by: Sohaib Mohamed <sohaib.amhmd@gmail.com>
> > ---
> > tools/perf/bench/find-bit-bench.c | 1 +
> > tools/perf/bench/synthesize.c | 2 ++
> > 2 files changed, 3 insertions(+)
> >
> > diff --git a/tools/perf/bench/find-bit-bench.c b/tools/perf/bench/find-bit-bench.c
> > index 22b5cfe97023..39fb4184fbcb 100644
> > --- a/tools/perf/bench/find-bit-bench.c
> > +++ b/tools/perf/bench/find-bit-bench.c
> > @@ -113,6 +113,7 @@ static int do_for_each_set_bit(unsigned int num_bits)
> >
> > if (use_of_val == accumulator) /* Try to avoid compiler tricks. */
> > printf("\n");
> > + fflush(stdout);
> > }
> > bitmap_free(to_test);
> > return 0;
> > diff --git a/tools/perf/bench/synthesize.c b/tools/perf/bench/synthesize.c
> > index 7401ebbac100..d21d311df61b 100644
> > --- a/tools/perf/bench/synthesize.c
> > +++ b/tools/perf/bench/synthesize.c
> > @@ -92,6 +92,7 @@ static int do_run_single_threaded(struct perf_session *session,
> > update_stats(&event_stats, atomic_read(&event_count));
> > }
> >
> > + fflush(stdout);
> > time_average = avg_stats(&time_stats);
> > time_stddev = stddev_stats(&time_stats);
> > printf(" Average %ssynthesis took: %.3f usec (+- %.3f usec)\n",
> > @@ -186,6 +187,7 @@ static int do_run_multi_threaded(struct target *target,
> > perf_session__delete(session);
> > }
> >
> > + fflush(stdout);
> > time_average = avg_stats(&time_stats);
> > time_stddev = stddev_stats(&time_stats);
> > printf(" Average synthesis took: %.3f usec (+- %.3f usec)\n",
> > --
> > 2.25.1
>
> --
>
> - Arnaldo

--

- Arnaldo