From 2c0c584c9ce8a5f3551a95c8bcfc6e0090b368d0 Mon Sep 17 00:00:00 2001 From: Michael Petlan Date: Fri, 27 Sep 2024 17:19:26 +0200 Subject: [PATCH] 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 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 --- 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 8449f2beb54d7..19db23f78b199 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -5038,6 +5038,10 @@ 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) { -- 2.47.2