From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752158AbaLRG3P (ORCPT ); Thu, 18 Dec 2014 01:29:15 -0500 Received: from terminus.zytor.com ([198.137.202.10]:58552 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751844AbaLRG3M (ORCPT ); Thu, 18 Dec 2014 01:29:12 -0500 Date: Wed, 17 Dec 2014 22:28:06 -0800 From: tip-bot for Arnaldo Carvalho de Melo Message-ID: Cc: mingo@kernel.org, paulus@samba.org, dsahern@gmail.com, namhyung@kernel.org, dzickus@redhat.com, acme@redhat.com, eranian@google.com, hpa@zytor.com, efault@gmx.de, jolsa@redhat.com, peterz@infradead.org, adrian.hunter@intel.com, bp@suse.de, tglx@linutronix.de, linux-kernel@vger.kernel.org, fweisbec@gmail.com Reply-To: mingo@kernel.org, paulus@samba.org, dsahern@gmail.com, namhyung@kernel.org, acme@redhat.com, dzickus@redhat.com, eranian@google.com, hpa@zytor.com, jolsa@redhat.com, efault@gmx.de, adrian.hunter@intel.com, peterz@infradead.org, bp@suse.de, tglx@linutronix.de, fweisbec@gmail.com, linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf evlist: Fixup brown paper bag on "hint" for --mmap-pages cmdline arg Git-Commit-ID: 0a2138b28fd56eeb3852133691c881409885ee3f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 0a2138b28fd56eeb3852133691c881409885ee3f Gitweb: http://git.kernel.org/tip/0a2138b28fd56eeb3852133691c881409885ee3f Author: Arnaldo Carvalho de Melo AuthorDate: Fri, 12 Dec 2014 16:07:47 -0300 Committer: Arnaldo Carvalho de Melo CommitDate: Tue, 16 Dec 2014 13:38:26 -0300 perf evlist: Fixup brown paper bag on "hint" for --mmap-pages cmdline arg When failing due to asking for a number of mmap pages that is more than the max, it was suggesting that an even bigger number of mmap pages should be specified, doh, au contraire! Before: [acme@ssdandy linux]$ trace -m 128 usleep 1 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting. Hint: Tried using 516 kB. Hint: Try using a bigger -m/--mmap-pages value. [acme@ssdandy linux]$ After: [acme@ssdandy linux]$ trace -m 128 usleep 1 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting. Hint: Tried using 516 kB. Hint: Try using a smaller -m/--mmap-pages value. [acme@ssdandy linux]$ And to (really) clarify what happens above, when what the user requests is <= max and even then it fails, a changeset is being made to tell that this is a per user limit, not per process (in the above example there was another 'perf trace' running for this user, which was using all the pages it could use). Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-8qope8lxb898narnq5kmu2gf@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index bb5dfc5..de7515d 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1495,7 +1495,7 @@ int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, s scnprintf(buf, size, "Error:\t%s.\n" "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n" "Hint:\tTried using %zd kB.\n" - "Hint:\tTry using a bigger -m/--mmap-pages value.", + "Hint:\tTry using a smaller -m/--mmap-pages value.", emsg, value, evlist->mmap_len / 1024); break; default: