perf stat: Add --log-fd <N> option to redirect stderr elsewhere
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. This complements --output file option, and is
mutually exclusive with it.
3>results perf stat --log-fd 3 -- $cmd
3>>results perf stat --log-fd 3 --append -- $cmd
The perl distro's make test.valgrind target uses valgrind's --log-fd
option, I've adapted it to invoke perf also, and tested this patch
there.
Link: http://lkml.kernel.org/r/1315437244-3788-2-git-send-email-jim.cromie@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index bec64a9..a43c680 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -196,6 +196,7 @@
static bool group = false;
static const char *output_name = NULL;
static FILE *output = NULL;
+static int output_fd;
static volatile int done = 0;
@@ -1080,6 +1081,8 @@
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()
};
@@ -1166,6 +1169,10 @@
if (output_name && strcmp(output_name, "-"))
output = NULL;
+ if (output_name && output_fd) {
+ fprintf(stderr, "cannot use both --output and --log-fd\n");
+ usage_with_options(stat_usage, options);
+ }
if (!output) {
struct timespec tm;
mode = append_file ? "a" : "w";
@@ -1177,6 +1184,13 @@
}
clock_gettime(CLOCK_REALTIME, &tm);
fprintf(output, "# started on %s\n", ctime(&tm.tv_sec));
+ } else if (output_fd != 2) {
+ mode = append_file ? "a" : "w";
+ output = fdopen(output_fd, mode);
+ if (!output) {
+ perror("Failed opening logfd");
+ return -errno;
+ }
}
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