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Date:   Mon, 27 Mar 2023 14:45:42 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Namhyung Kim <namhyung@kernel.org>
Cc:     Yang Jihong <yangjihong1@huawei.com>, peterz@infradead.org,
        mingo@redhat.com, mark.rutland@arm.com,
        alexander.shishkin@linux.intel.com, jolsa@kernel.org,
        irogers@google.com, adrian.hunter@intel.com,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf ftrace: Make system wide the default target for
 latency subcommand
Message-ID: <ZCHWRpv5nDVQLR5s@kernel.org>
References: <20230324032702.109964-1-yangjihong1@huawei.com>
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 <ZCF/Oa+dK4Wc/7r7@kernel.org>
 <CAM9d7cgHAkWQ+5yo9WuociTM_p8vghPPDT+Gtm4HAt_LqrzzTQ@mail.gmail.com>
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Em Mon, Mar 27, 2023 at 07:58:43AM -0700, Namhyung Kim escreveu:
> On Mon, Mar 27, 2023 at 4:34 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Em Fri, Mar 24, 2023 at 06:39:25PM -0700, Namhyung Kim escreveu:
> > > Hello,
> > >
> > > On Thu, Mar 23, 2023 at 8:29 PM Yang Jihong <yangjihong1@huawei.com> wrote:
> > > >
> > > > If no target is specified for 'latency' subcommand, the execution fails
> > > > because - 1 (invalid value) is written to set_ftrace_pid tracefs file.
> > > > Make system wide the default target, which is the same as the default
> > > > behavior of 'trace' subcommand.
> > >
> > > I followed the convention to use -a for system-wide profiling.
> > > Not sure if it's ok to make it default, but I don't object. :)
> >
> > I'll make that an Acked-by, ok?
> 
> Sure.
> 
> Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks!

- Arnaldo
 
> Thanks,
> Namhyung
> 
> 
> > > >
> > > > Before the fix:
> > > >
> > > >   # perf ftrace latency -T schedule
> > > >   failed to set ftrace pid
> > > >
> > > > After the fix:
> > > >
> > > >   # perf ftrace latency -T schedule
> > > >   ^C#   DURATION     |      COUNT | GRAPH                                          |
> > > >        0 - 1    us |          0 |                                                |
> > > >        1 - 2    us |          0 |                                                |
> > > >        2 - 4    us |          0 |                                                |
> > > >        4 - 8    us |       2828 | ####                                           |
> > > >        8 - 16   us |      23953 | ########################################       |
> > > >       16 - 32   us |        408 |                                                |
> > > >       32 - 64   us |        318 |                                                |
> > > >       64 - 128  us |          4 |                                                |
> > > >      128 - 256  us |          3 |                                                |
> > > >      256 - 512  us |          0 |                                                |
> > > >      512 - 1024 us |          1 |                                                |
> > > >        1 - 2    ms |          4 |                                                |
> > > >        2 - 4    ms |          0 |                                                |
> > > >        4 - 8    ms |          0 |                                                |
> > > >        8 - 16   ms |          0 |                                                |
> > > >       16 - 32   ms |          0 |                                                |
> > > >       32 - 64   ms |          0 |                                                |
> > > >       64 - 128  ms |          0 |                                                |
> > > >      128 - 256  ms |          4 |                                                |
> > > >      256 - 512  ms |          2 |                                                |
> > > >      512 - 1024 ms |          0 |                                                |
> > > >        1 - ...   s |          0 |                                                |
> > > >
> > > > Fixes: 53be50282269 ("perf ftrace: Add 'latency' subcommand")
> > > > Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
> > > > ---
> > > >  tools/perf/builtin-ftrace.c | 6 ++++--
> > > >  1 file changed, 4 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > > > index d7fe00f66b83..fb1b66ef2e16 100644
> > > > --- a/tools/perf/builtin-ftrace.c
> > > > +++ b/tools/perf/builtin-ftrace.c
> > > > @@ -1228,10 +1228,12 @@ int cmd_ftrace(int argc, const char **argv)
> > > >                 goto out_delete_filters;
> > > >         }
> > > >
> > > > +       /* Make system wide (-a) the default target. */
> > > > +       if (!argc && target__none(&ftrace.target))
> > > > +               ftrace.target.system_wide = true;
> > > > +
> > > >         switch (subcmd) {
> > > >         case PERF_FTRACE_TRACE:
> > > > -               if (!argc && target__none(&ftrace.target))
> > > > -                       ftrace.target.system_wide = true;
> > > >                 cmd_func = __cmd_ftrace;
> > > >                 break;
> > > >         case PERF_FTRACE_LATENCY:
> > > > --
> > > > 2.30.GIT
> > > >
> >
> > --
> >
> > - Arnaldo

-- 

- Arnaldo