Re: [PATCH 1/2] perf stat: add -l <N> option to redirect stderr elsewhere

[Arnaldo Carvalho de Melo <acme@ghostprotocols.net>]

Em Fri, Sep 02, 2011 at 12:04:03PM -0600, Jim Cromie escreveu:
> On Fri, Sep 2, 2011 at 8:35 AM, Arnaldo Carvalho de Melo
> <acme@ghostprotocols.net> wrote:
> > Em Thu, Sep 01, 2011 at 03:58:13PM -0600, Jim Cromie escreveu:
> >> On Sat, May 21, 2011 at 2:41 PM, Arnaldo Carvalho de Melo
> >> <acme@ghostprotocols.net> wrote:
> >> > Em Sat, May 21, 2011 at 12:34:18PM +0200, Ingo Molnar escreveu:
> >> >> * Jim Cromie <jim.cromie@gmail.com> wrote:
> >> >>
> >> >> > This perf stat option emulates valgrind's --log-fd option, allowing the
> >> >> > user to send perf results elsewhere, and leaving stderr for use by the
> >> >> > program under test.
> >> >> >
> >> >> >   3>results perf stat -l 3 -- <cmd>
> >> >> >
> >> >> > The perl distro's make test.valgrind target uses valgrinds --log-fd
> >> >> > option, I've adapted it to invoke perf also, and tested this patch there.
> >> >> >
> >> >> > Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
> >> >>
> >> >> Makes sense!
> >> >>
> >> >> Arnaldo, if you are fine with it, do you want to pick it up - or should i? If
> >> >> you pick it up:
> >> >>
> >> >> Acked-by: Ingo Molnar <mingo@elte.hu>
> >> >
> >> > Its ok with me:
> >> >
> >> > Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> >> >
> >> > I will pick it this weekend, if you don't merge it till then.
> >
> >> Did this ever happen ?
> >> Can you point me to the git-url where it did/will end up ?
> >
> > Fell thru the cracks, then Stephane implemented --output:
> >
> > http://git.kernel.org/?p=linux/kernel/git/tip/linux-tip.git;a=commitdiff;h=4aa9015f8bfd2c8d7cc33a360275b71a9d708b37
> >
> > That introduces an output FILE pointer as in your patch (logfp), so I
> > adjusted your patch, that ended up like below. I removed -l and made it
> > --log-fd, just like valgrind and added the Documentation bits about the
> > new cmdline option, ok?
> >
> 
> absolutely.
> theres one comment I added (just above output_fd decl)
> that mentions -I, it should be updated to --log-fd
> 
> And probably --output and --log-fd should be mutually exclusive.

With the current implementation if --output is used --log-fd will be
ignored if present, perhaps we should print a warning or plain fail if
the user tries to specify both?
 
> > I'll look at the other 3 patch series that came after, will fix up and
> > post here for your consideration.
> 
> those are the output format refactoring ?
> 
> ah, your new message just arrived.
> I'll take another go at them..

Ok, please apply this reworked --log-fd before, of course :)

> thanks
> 
> >
> > - Arnaldo
> >
> > diff --git a/tools/perf/Documentation/perf-stat.txt b/tools/perf/Documentation/perf-stat.txt
> > index 08394c4..b6bfd1e 100644
> > --- a/tools/perf/Documentation/perf-stat.txt
> > +++ b/tools/perf/Documentation/perf-stat.txt
> > @@ -101,6 +101,9 @@ Print the output into the designated file.
> >  --append::
> >  Append to the output file designated with the -o option. Ignored if -o is not specified.
> >
> > +--log-fd::
> > +Log output to fd, instead of stderr.
> 
> stderr / outputfile ??
> 
> > +
> >  EXAMPLES
> >  --------
> >
> > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> > index bec64a9..c991d66 100644
> > --- a/tools/perf/builtin-stat.c
> > +++ b/tools/perf/builtin-stat.c
> > @@ -196,6 +196,8 @@ static bool                 csv_output                      = false;
> >  static bool                    group                           = false;
> >  static const char              *output_name                    = NULL;
> >  static FILE                    *output                         = NULL;
> > +/* stderr by default, override with -l */
> 
> with --log-fd

Can you rework it and put as the first on your new patchset?

Thanks,

- Arnaldo
 
> > +static int                     output_fd                       = 2;
> >
> >  static volatile int done = 0;
> >
> > @@ -1080,6 +1082,8 @@ static const struct option options[] = {
> >        OPT_STRING('o', "output", &output_name, "file",
> >                    "output file name"),
> >        OPT_BOOLEAN(0, "append", &append_file, "append to the output file"),
> > +       OPT_INTEGER(0, "log-fd", &output_fd,
> > +                   "log output to fd, instead of stderr"),
> >        OPT_END()
> >  };
> >
> > @@ -1177,6 +1181,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used)
> >                }
> >                clock_gettime(CLOCK_REALTIME, &tm);
> >                fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
> > +       } else if (output_fd != 2) {
> > +               output = fdopen(output_fd, "w");
> > +               if (!output) {
> > +                       perror("Failed opening logfd");
> > +                       return -errno;
> > +               }
> >        }
> >
> >        if (csv_sep)
> >