This is a note to let you know that I've just added the patch titled
perf inject: Fix --buildid-all not to eat up MMAP2
to the 6.1-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-inject-fix-buildid-all-not-to-eat-up-mmap2.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ce9f1c05d2edfa6cdf2c1a510495d333e11810a8 Mon Sep 17 00:00:00 2001
From: Namhyung Kim <namhyung@xxxxxxxxxx>
Date: Wed, 22 Feb 2023 23:01:55 -0800
Subject: perf inject: Fix --buildid-all not to eat up MMAP2
From: Namhyung Kim <namhyung@xxxxxxxxxx>
commit ce9f1c05d2edfa6cdf2c1a510495d333e11810a8 upstream.
When MMAP2 has the PERF_RECORD_MISC_MMAP_BUILD_ID flag, it means the
record already has the build-id info. So it marks the DSO as hit, to
skip if the same DSO is not processed if it happens to miss the build-id
later.
But it missed to copy the MMAP2 record itself so it'd fail to symbolize
samples for those regions.
For example, the following generates 249 MMAP2 events.
$ perf record --buildid-mmap -o- true | perf report --stat -i- | grep MMAP2
MMAP2 events: 249 (86.8%)
Adding perf inject should not change the number of events like this
$ perf record --buildid-mmap -o- true | perf inject -b | \
> perf report --stat -i- | grep MMAP2
MMAP2 events: 249 (86.5%)
But when --buildid-all is used, it eats most of the MMAP2 events.
$ perf record --buildid-mmap -o- true | perf inject -b --buildid-all | \
> perf report --stat -i- | grep MMAP2
MMAP2 events: 1 ( 2.5%)
With this patch, it shows the original number now.
$ perf record --buildid-mmap -o- true | perf inject -b --buildid-all | \
> perf report --stat -i- | grep MMAP2
MMAP2 events: 249 (86.5%)
Committer testing:
Before:
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf inject -b | perf report --stat -i- | grep MMAP2
MMAP2 events: 58 (36.2%)
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf report --stat -i- | grep MMAP2
MMAP2 events: 58 (36.2%)
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf inject -b --buildid-all | perf report --stat -i- | grep MMAP2
MMAP2 events: 2 ( 1.9%)
$
After:
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf inject -b | perf report --stat -i- | grep MMAP2
MMAP2 events: 58 (29.3%)
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf report --stat -i- | grep MMAP2
MMAP2 events: 58 (34.3%)
$ perf record --buildid-mmap -o- perf stat --null sleep 1 2> /dev/null | perf inject -b --buildid-all | perf report --stat -i- | grep MMAP2
MMAP2 events: 58 (38.4%)
$
Fixes: f7fc0d1c915a74ff ("perf inject: Do not inject BUILD_ID record if MMAP2 has it")
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20230223070155.54251-1-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/builtin-inject.c | 1 +
1 file changed, 1 insertion(+)
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -538,6 +538,7 @@ static int perf_event__repipe_buildid_mm
dso->hit = 1;
}
dso__put(dso);
+ perf_event__repipe(tool, event, sample, machine);
return 0;
}
Patches currently in stable-queue which might be from namhyung@xxxxxxxxxx are
queue-6.1/perf-inject-fix-buildid-all-not-to-eat-up-mmap2.patch
