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

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

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?

I'll look at the other 3 patch series that came after, will fix up and
post here for your consideration.

- 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.
+
 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 */
+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)