linux-kernel - Re: [PATCH] perf script: print cgroup on the same line as comm

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Date:   Mon, 7 Aug 2023 11:02:01 -0700
From:   Ivan Babrou <ivan@...udflare.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Ian Rogers <irogers@...gle.com>, linux-perf-users@...r.kernel.org,
        kernel-team@...udflare.com, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH] perf script: print cgroup on the same line as comm

On Fri, Jul 28, 2023 at 10:57 AM Ian Rogers <irogers@...gle.com> wrote:
>
> On Fri, Jul 28, 2023 at 10:42 AM Ivan Babrou <ivan@...udflare.com> wrote:
> >
> > On Mon, Jul 17, 2023 at 5:07 PM Ivan Babrou <ivan@...udflare.com> wrote:
> > >
> > > Commit 3fd7a168bf51 ("perf script: Add 'cgroup' field for output")
> > > added support for printing cgroup path in perf script output.
> > >
> > > It was okay if you didn't want any stacks:
> > >
> > >     $ sudo perf script --comms jpegtran:23f4bf -F comm,tid,cpu,time,cgroup
> > >     jpegtran:23f4bf 3321915 [013] 404718.587488:  /idle.slice/polish.service
> > >     jpegtran:23f4bf 3321915 [031] 404718.592073:  /idle.slice/polish.service
> > >
> > > With stacks it gets messier as cgroup is printed after the stack:
> > >
> > >     $ perf script --comms jpegtran:23f4bf -F comm,tid,cpu,time,cgroup,ip,sym
> > >     jpegtran:23f4bf 3321915 [013] 404718.587488:
> > >                     5c554 compress_output
> > >                     570d9 jpeg_finish_compress
> > >                     3476e jpegtran_main
> > >                     330ee jpegtran::main
> > >                     326e2 core::ops::function::FnOnce::call_once (inlined)
> > >                     326e2 std::sys_common::backtrace::__rust_begin_short_backtrace
> > >     /idle.slice/polish.service
> > >     jpegtran:23f4bf 3321915 [031] 404718.592073:
> > >                     8474d jsimd_encode_mcu_AC_first_prepare_sse2.PADDING
> > >                 55af68e62fff [unknown]
> > >     /idle.slice/polish.service
> > >
> > > Let's instead print cgroup on the same line as comm:
> > >
> > >     $ perf script --comms jpegtran:23f4bf -F comm,tid,cpu,time,cgroup,ip,sym
> > >     jpegtran:23f4bf 3321915 [013] 404718.587488:  /idle.slice/polish.service
> > >                     5c554 compress_output
> > >                     570d9 jpeg_finish_compress
> > >                     3476e jpegtran_main
> > >                     330ee jpegtran::main
> > >                     326e2 core::ops::function::FnOnce::call_once (inlined)
> > >                     326e2 std::sys_common::backtrace::__rust_begin_short_backtrace
> > >
> > >     jpegtran:23f4bf 3321915 [031] 404718.592073:  /idle.slice/polish.service
> > >                     8474d jsimd_encode_mcu_AC_first_prepare_sse2.PADDING
> > >                 55af68e62fff [unknown]
> > >
> > > Signed-off-by: Ivan Babrou <ivan@...udflare.com>
> > > Fixes: 3fd7a168bf51 ("perf script: Add 'cgroup' field for output")
>
> This change makes sense to me. Namhyung, wdyt?
>
> Thanks,
> Ian

Hi Namhyung,

This is a really trivial patch and it would be good to get a word from you.

Thanks.

> > > ---
> > >  tools/perf/builtin-script.c | 22 +++++++++++-----------
> > >  1 file changed, 11 insertions(+), 11 deletions(-)
> > >
> > > diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> > > index 200b3e7ea8da..517bf25750c8 100644
> > > --- a/tools/perf/builtin-script.c
> > > +++ b/tools/perf/builtin-script.c
> > > @@ -2199,6 +2199,17 @@ static void process_event(struct perf_script *script,
> > >         if (PRINT_FIELD(RETIRE_LAT))
> > >                 fprintf(fp, "%16" PRIu16, sample->retire_lat);
> > >
> > > +       if (PRINT_FIELD(CGROUP)) {
> > > +               const char *cgrp_name;
> > > +               struct cgroup *cgrp = cgroup__find(machine->env,
> > > +                                                  sample->cgroup);
> > > +               if (cgrp != NULL)
> > > +                       cgrp_name = cgrp->name;
> > > +               else
> > > +                       cgrp_name = "unknown";
> > > +               fprintf(fp, " %s", cgrp_name);
> > > +       }
> > > +
> > >         if (PRINT_FIELD(IP)) {
> > >                 struct callchain_cursor *cursor = NULL;
> > >
> > > @@ -2243,17 +2254,6 @@ static void process_event(struct perf_script *script,
> > >         if (PRINT_FIELD(CODE_PAGE_SIZE))
> > >                 fprintf(fp, " %s", get_page_size_name(sample->code_page_size, str));
> > >
> > > -       if (PRINT_FIELD(CGROUP)) {
> > > -               const char *cgrp_name;
> > > -               struct cgroup *cgrp = cgroup__find(machine->env,
> > > -                                                  sample->cgroup);
> > > -               if (cgrp != NULL)
> > > -                       cgrp_name = cgrp->name;
> > > -               else
> > > -                       cgrp_name = "unknown";
> > > -               fprintf(fp, " %s", cgrp_name);
> > > -       }
> > > -
> > >         perf_sample__fprintf_ipc(sample, attr, fp);
> > >
> > >         fprintf(fp, "\n");
> > > --
> > > 2.41.0
> > >
> >
> > A friendly bump in case this slipped through the cracks.