This is a note to let you know that I've just added the patch titled
perf bench: Use unbuffered output when pipe/tee'ing to a file
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-bench-use-unbuffered-output-when-pipe-tee-ing-t.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e2a7f4dc654559283fd4fbd73f29f426afaec03e
Author: Sohaib Mohamed <sohaib.amhmd@xxxxxxxxx>
Date: Fri Nov 19 08:14:08 2021 +0200
perf bench: Use unbuffered output when pipe/tee'ing to a file
[ Upstream commit f0a29c9647ff8bbb424641f79bc1894e83dec218 ]
The output of 'perf bench' gets buffered when I pipe it to a file or to
tee, in such a way that I can see it only at the end.
E.g.
$ perf bench internals synthesize -t
< output comes out fine after each test run >
$ perf bench internals synthesize -t | tee file.txt
< output comes out only at the end of all tests >
This patch resolves this issue for 'bench' and 'test' subcommands.
See, also:
$ perf bench mem all | tee file.txt
$ perf bench sched all | tee file.txt
$ perf bench internals all -t | tee file.txt
$ perf bench internals all | tee file.txt
Committer testing:
It really gets staggered, i.e. outputs in bursts, when the buffer fills
up and has to be drained to make up space for more output.
Suggested-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
Signed-off-by: Sohaib Mohamed <sohaib.amhmd@xxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Fabian Hemmer <copy@xxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20211119061409.78004-1-sohaib.amhmd@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Stable-dep-of: 16203e9cd018 ("perf bench: Add missing setlocale() call to allow usage of %'d style formatting")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/builtin-bench.c b/tools/perf/builtin-bench.c
index d0895162c2ba6..d291f3a8af5f2 100644
--- a/tools/perf/builtin-bench.c
+++ b/tools/perf/builtin-bench.c
@@ -226,7 +226,6 @@ static void run_collection(struct collection *coll)
if (!bench->fn)
break;
printf("# Running %s/%s benchmark...\n", coll->name, bench->name);
- fflush(stdout);
argv[1] = bench->name;
run_bench(coll->name, bench->name, bench->fn, 1, argv);
@@ -247,6 +246,9 @@ int cmd_bench(int argc, const char **argv)
struct collection *coll;
int ret = 0;
+ /* Unbuffered output */
+ setvbuf(stdout, NULL, _IONBF, 0);
+
if (argc < 2) {
/* No collection specified. */
print_usage();
@@ -300,7 +302,6 @@ int cmd_bench(int argc, const char **argv)
if (bench_format == BENCH_FORMAT_DEFAULT)
printf("# Running '%s/%s' benchmark:\n", coll->name, bench->name);
- fflush(stdout);
ret = run_bench(coll->name, bench->name, bench->fn, argc-1, argv+1);
goto end;
}
diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
index da7dc5e45d0cf..4d6d3e3142008 100644
--- a/tools/perf/tests/builtin-test.c
+++ b/tools/perf/tests/builtin-test.c
@@ -828,6 +828,9 @@ int cmd_test(int argc, const char **argv)
if (ret < 0)
return ret;
+ /* Unbuffered output */
+ setvbuf(stdout, NULL, _IONBF, 0);
+
argc = parse_options_subcommand(argc, argv, test_options, test_subcommands, test_usage, 0);
if (argc >= 1 && !strcmp(argv[0], "list"))
return perf_test__list(argc - 1, argv + 1);
