From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934004AbcLMPKi (ORCPT ); Tue, 13 Dec 2016 10:10:38 -0500 Received: from merlin.infradead.org ([205.233.59.134]:38422 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933658AbcLMPKd (ORCPT ); Tue, 13 Dec 2016 10:10:33 -0500 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Jiri Olsa , David Ahern , Namhyung Kim , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 21/22] perf record: Force ignore_missing_thread for uid option Date: Tue, 13 Dec 2016 12:09:27 -0300 Message-Id: <20161213150928.13144-22-acme@kernel.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20161213150928.13144-1-acme@kernel.org> References: <20161213150928.13144-1-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa 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 Tested-by: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1481538943-21874-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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); -- 2.9.3