From: Namhyung Kim Date: Fri, 27 Aug 2021 23:32:12 +0000 (-0700) Subject: perf record: Fix wrong comm in system-wide mode with delay X-Git-Tag: microblaze-v5.16~86^2~40 X-Git-Url: http://git.monstr.eu/?p=linux-2.6-microblaze.git;a=commitdiff_plain;h=bb07d62e039b592f8006c9faedab48cd627e20c4 perf record: Fix wrong comm in system-wide mode with delay Stephane found that the name of the forked process in a system-wide mode is wrong when --delay option is used. For example, # perf record -a --delay=1000 noploop 3 The noploop process will run a busy loop for 3 second. And on an idle machine it should show up at the top in the perf report. It works well without the --delay option. But if I add the option, it showed 'perf' not 'noploop'. # perf report -s comm -q | head -3 52.94% perf 16.65% swapper 12.04% chrome It turned out that the dummy event didn't work at all and it missed COMM and MMAP events for the noploop process (and others too). We should enable the dummy event immediately in system-wide mode, as the enable-on-exec would work only for task events. With this change, # perf report -s comm -q | head -3 52.75% noploop 17.03% swapper 12.83% chrome Reported-by: Stephane Eranian Signed-off-by: Namhyung Kim Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Andi Kleen Cc: Jiri Olsa Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20210827233212.3121037-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index cc801fecf079..06c4dca0c466 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -910,7 +910,8 @@ static int record__open(struct record *rec) * Enable the dummy event when the process is forked for * initial_delay, immediately for system wide. */ - if (opts->initial_delay && !pos->immediate) + if (opts->initial_delay && !pos->immediate && + !target__has_cpu(&opts->target)) pos->core.attr.enable_on_exec = 1; else pos->immediate = 1;