Messages in this thread | | | Date | Mon, 4 Jun 2012 09:31:22 +0200 | Subject | Re: [PATCH] perf stat: fix default output file | From | Stephane Eranian <> |
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Ping?
On Tue, May 15, 2012 at 1:11 PM, Stephane Eranian <eranian@google.com> wrote: > > The following commit: > > commit 56f3bae70638b33477a6015fd362ccfe354fd3ee > Author: Jim Cromie <jim.cromie@gmail.com> > Date: Wed Sep 7 17:14:00 2011 -0600 > > perf stat: Add --log-fd <N> option to redirect stderr elsewhere > > introduced a bug in the way perf stat outputs the results by default, i.e., > without the --log-fd or --output option. It would default to writing to > file descriptor 0, i.e., stdin. Writing to stdin is allowed and is equivalent > to writing to stdout. However, there is a major difference for any script that > was already capturing the output of perf stat via redirection: > > perf stat >/tmp/log .... or perf stat 2>/tmp/log .... > > They would not capture anything anymore. They would have to do: > perf stat 0>/tmp/log ... > > This breaks compatibility with existing scripts and does not look very > natural. > > This patch fixes the problem by looking at output_fd only when it > was modified by user (> 0). It also checks that the value if positive. > Passing --log-fd 0 is ignored. > > I would also argue that defaulting to stderr for the results is not > the right thing to do, though this patch does not address this specific > issue. > > Signed-off-by: Stephane Eranian <eranian@google.com> > --- > > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index 36603e4..56e6040 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -1179,6 +1179,12 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used) > fprintf(stderr, "cannot use both --output and --log-fd\n"); > usage_with_options(stat_usage, options); > } > + > + if (output_fd < 0) { > + fprintf(stderr, "argument to --log-fd must be a > 0\n"); > + usage_with_options(stat_usage, options); > + } > + > if (!output) { > struct timespec tm; > mode = append_file ? "a" : "w"; > @@ -1190,7 +1196,7 @@ 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) { > + } else if (output_fd > 0) { > mode = append_file ? "a" : "w"; > output = fdopen(output_fd, mode); > if (!output) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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