linux-kernel - Re: [PATCH v3] perf c2c: fix '-e list'

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Date:   Mon, 11 May 2020 13:29:42 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     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>,
        Namhyung Kim <namhyung@...nel.org>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v3] perf c2c: fix '-e list'

On Mon, May 11, 2020 at 12:36 PM Jiri Olsa <jolsa@...hat.com> wrote:
>
> On Thu, May 07, 2020 at 03:06:04PM -0700, Ian Rogers wrote:
> > When the event is passed as list, the default events should be listed as
> > per 'perf mem record -e list'. Previous behavior is:
> >
> > $ perf c2c record -e list
> > failed: event 'list' not found, use '-e list' to get list of available events
> >
> >  Usage: perf c2c record [<options>] [<command>]
> >     or: perf c2c record [<options>] -- <command> [<options>]
> >
> >     -e, --event <event>   event selector. Use 'perf mem record -e list' to list available events
> >
> > New behavior:
> >
> > $ perf c2c record -e list
> > ldlat-loads  : available
> > ldlat-stores : available
> >
> > v3: is a rebase.
> > v2: addresses review comments by Jiri Olsa.
> > https://lore.kernel.org/lkml/20191127081844.GH32367@krava/
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> >  tools/perf/Documentation/perf-c2c.txt |  2 +-
> >  tools/perf/builtin-c2c.c              |  9 ++++++++-
> >  tools/perf/builtin-mem.c              | 24 +++++++-----------------
> >  tools/perf/util/mem-events.c          | 15 +++++++++++++++
> >  tools/perf/util/mem-events.h          |  2 ++
> >  5 files changed, 33 insertions(+), 19 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt
> > index 2133eb320cb0..98efdab5fbd4 100644
> > --- a/tools/perf/Documentation/perf-c2c.txt
> > +++ b/tools/perf/Documentation/perf-c2c.txt
> > @@ -40,7 +40,7 @@ RECORD OPTIONS
> >  --------------
> >  -e::
> >  --event=::
> > -     Select the PMU event. Use 'perf mem record -e list'
> > +     Select the PMU event. Use 'perf c2c record -e list'
> >       to list available events.
> >
> >  -v::
> > diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> > index 1baf4cae086f..d617d5682c68 100644
> > --- a/tools/perf/builtin-c2c.c
> > +++ b/tools/perf/builtin-c2c.c
> > @@ -2887,8 +2887,15 @@ static int parse_record_events(const struct option *opt,
> >  {
> >       bool *event_set = (bool *) opt->value;
> >
> > +     if (!strcmp(str, "list")) {
> > +             perf_mem_events__list();
> > +             exit(0);
> > +     }
> > +     if (perf_mem_events__parse(str))
> > +             exit(-1);
>
> won't this exit(-1) callsbreak the parsing stuff?
> like displaying the option values on error or such?

The previous code was:
-       if (strcmp(str, "list")) {
This is handled explicitly in the code above this.

-               if (!perf_mem_events__parse(str)) {
-                       mem->operation = 0;
-                       return 0;
-               }
-               exit(-1);
This is the code where the exit -1 happens, I inverted the comparison
so that exit was more the exceptional code path. The behavior should
be identical.

Thanks,
Ian

> other than that it looks ok to me
>
> jirka
>