This is a note to let you know that I've just added the patch titled
perf trace: Keep exited threads for summary
to the 6.6-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-trace-keep-exited-threads-for-summary.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 43b474ff9bb6ca938482882548e0860f972eee8e
Author: Michael Petlan <mpetlan@xxxxxxxxxx>
Date: Fri Sep 27 17:19:26 2024 +0200
perf trace: Keep exited threads for summary
[ Upstream commit d29d92df410e2fb523f640478b18f70c1823e55e ]
Since 9ffa6c7512ca ("perf machine thread: Remove exited threads by
default") perf cleans exited threads up, but as said, sometimes they
are necessary to be kept. The mentioned commit does not cover all the
cases, we also need the information to construct the summary table in
perf-trace.
Before:
# perf trace -s true
Summary of events:
After:
# perf trace -s -- true
Summary of events:
true (383382), 64 events, 91.4%
syscall calls errors total min avg max stddev
(msec) (msec) (msec) (msec) (%)
--------------- -------- ------ -------- --------- --------- --------- ------
mmap 8 0 0.150 0.013 0.019 0.031 11.90%
mprotect 3 0 0.045 0.014 0.015 0.017 6.47%
openat 2 0 0.014 0.006 0.007 0.007 9.73%
munmap 1 0 0.009 0.009 0.009 0.009 0.00%
access 1 1 0.009 0.009 0.009 0.009 0.00%
pread64 4 0 0.006 0.001 0.001 0.002 4.53%
fstat 2 0 0.005 0.001 0.002 0.003 37.59%
arch_prctl 2 1 0.003 0.001 0.002 0.002 25.91%
read 1 0 0.003 0.003 0.003 0.003 0.00%
close 2 0 0.003 0.001 0.001 0.001 3.86%
brk 1 0 0.002 0.002 0.002 0.002 0.00%
rseq 1 0 0.001 0.001 0.001 0.001 0.00%
prlimit64 1 0 0.001 0.001 0.001 0.001 0.00%
set_robust_list 1 0 0.001 0.001 0.001 0.001 0.00%
set_tid_address 1 0 0.001 0.001 0.001 0.001 0.00%
execve 1 0 0.000 0.000 0.000 0.000 0.00%
[namhyung: simplified the condition]
Fixes: 9ffa6c7512ca ("perf machine thread: Remove exited threads by default")
Reported-by: Veronika Molnarova <vmolnaro@xxxxxxxxxx>
Signed-off-by: Michael Petlan <mpetlan@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240927151926.399474-1-mpetlan@xxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index e541d0e2777ab..6fd30bddf0de9 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -5031,6 +5031,10 @@ int cmd_trace(int argc, const char **argv)
if (trace.summary_only)
trace.summary = trace.summary_only;
+ /* Keep exited threads, otherwise information might be lost for summary */
+ if (trace.summary)
+ symbol_conf.keep_exited_threads = true;
+
if (output_name != NULL) {
err = trace__open_output(&trace, output_name);
if (err < 0) {
