From 23dc4f1586159470aac707caae526824dd077e25 Mon Sep 17 00:00:00 2001 From: Jiri Olsa <jolsa@kernel.org> Date: Mon, 12 Dec 2016 11:35:43 +0100 Subject: [PATCH] perf record: Force ignore_missing_thread for uid option Enable perf_evsel::ignore_missing_thread for -u option to ignore complete failure if any of the user's processes die between its enumeration and time we open the event. Committer notes: While doing a 'make -j4 allmodconfig' we sometimes get into the race: Before: # perf record -u acme Error: The sys_perf_event_open() syscall returned with 3 (No such process) for event (cycles:ppp). /bin/dmesg may provide additional information. No CONFIG_PERF_EVENTS=y kernel support configured? # After: [root@jouet ~]# perf record -u acme WARNING: Ignored open failure for pid 9888 WARNING: Ignored open failure for pid 18059 [root@jouet ~]# Which is an improvement, with the races not preventing the remaining threads for the specified user from being monitored, but the message probably needs further clarification. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1481538943-21874-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/builtin-record.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index fa26865364b6..74d6a035133a 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1687,6 +1687,9 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused) goto out; } + /* Enable ignoring missing threads when -u option is defined. */ + rec->opts.ignore_missing_thread = rec->opts.target.uid != UINT_MAX; + err = -ENOMEM; if (perf_evlist__create_maps(rec->evlist, &rec->opts.target) < 0) usage_with_options(record_usage, record_options);