6.6-stable review patch. If anyone has any objections, please let me know.
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From: Michael Petlan mpetlan@redhat.com
[ 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@redhat.com Signed-off-by: Michael Petlan mpetlan@redhat.com Link: https://lore.kernel.org/r/20240927151926.399474-1-mpetlan@redhat.com Signed-off-by: Namhyung Kim namhyung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/builtin-trace.c | 4 ++++ 1 file changed, 4 insertions(+)
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) {