From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1949561AbcBSWl4 (ORCPT ); Fri, 19 Feb 2016 17:41:56 -0500 Received: from casper.infradead.org ([85.118.1.10]:37481 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1949394AbcBSWlt (ORCPT ); Fri, 19 Feb 2016 17:41:49 -0500 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Jiri Olsa , Namhyung Kim , Steven Noonan , Wang Nan Subject: [PATCH 05/22] perf test: Reduce the sample_freq for the 'object code reading' test Date: Fri, 19 Feb 2016 19:41:19 -0300 Message-Id: <1455921696-3895-6-git-send-email-acme@kernel.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1455921696-3895-1-git-send-email-acme@kernel.org> References: <1455921696-3895-1-git-send-email-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.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: Arnaldo Carvalho de Melo Using 4 kHz is not necessary and sometimes is more than what was auto-tuned: # dmesg | grep max_sample_rate | tail -2 [ 2499.144373] perf interrupt took too long (2501 > 2500), lowering kernel.perf_event_max_sample_rate to 50000 [ 3592.413606] perf interrupt took too long (5069 > 5000), lowering kernel.perf_event_max_sample_rate to 25000 Simulating a auto-tune of 2000 we make the test fail, as reported by Steven Noonan for one of his machines, so reduce it to 500 HZ, it is enough to get a good number of samples for this test: # perf test -v 21 2>&1 | grep '^Reading object code for memory address' | tee /tmp/out | tail -5 Reading object code for memory address: 0x479f40 Reading object code for memory address: 0x7f29b7eea80d Reading object code for memory address: 0x7f29b7eea80d Reading object code for memory address: 0x7f29b7eea800 Reading object code for memory address: 0xffffffff813b2f23 [root@jouet ~]# wc -l /tmp/out 40 /tmp/out [root@jouet ~]# For systems that auto-tune below that, the previous patches will tell the user what is happening so that he may either ignore the result of this test or bump /proc/sys/kernel/perf_event_max_sample_rate. Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Cc: Steven Noonan Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-6kufyy1iprdfzrbtuqgxir70@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/tests/code-reading.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c index f84339cb7f95..afc9ad0a0515 100644 --- a/tools/perf/tests/code-reading.c +++ b/tools/perf/tests/code-reading.c @@ -439,7 +439,7 @@ static int do_test_code_reading(bool try_kcore) .mmap_pages = UINT_MAX, .user_freq = UINT_MAX, .user_interval = ULLONG_MAX, - .freq = 4000, + .freq = 500, .target = { .uses_mmap = true, }, -- 2.5.0