From 130f38d0d5c9d1bd1d28b5d4b7d2361acfe21437 Mon Sep 17 00:00:00 2001 From: Michael Petlan Date: Tue, 11 Mar 2025 08:51:19 +0900 Subject: [PATCH] perf trace: Keep exited threads for summary BugLink: https://bugs.launchpad.net/bugs/2101915 [ 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 Signed-off-by: Michael Petlan Link: https://lore.kernel.org/r/20240927151926.399474-1-mpetlan@redhat.com Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- 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 109b8e64fe69..a49ba07ae4cb 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -5029,6 +5029,10 @@ init_augmented_syscall_tp: 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) {