From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932889AbeBPJwd (ORCPT ); Fri, 16 Feb 2018 04:52:33 -0500 Received: from terminus.zytor.com ([198.137.202.136]:60517 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932850AbeBPJwa (ORCPT ); Fri, 16 Feb 2018 04:52:30 -0500 Date: Fri, 16 Feb 2018 01:42:06 -0800 From: tip-bot for Kan Liang Message-ID: Cc: yao.jin@linux.intel.com, mingo@kernel.org, wangnan0@huawei.com, namhyung@kernel.org, jolsa@kernel.org, kan.liang@intel.com, acme@redhat.com, tglx@linutronix.de, hpa@zytor.com, ak@linux.intel.com, peterz@infradead.org, linux-kernel@vger.kernel.org Reply-To: kan.liang@intel.com, acme@redhat.com, tglx@linutronix.de, yao.jin@linux.intel.com, mingo@kernel.org, wangnan0@huawei.com, namhyung@kernel.org, jolsa@kernel.org, peterz@infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com, ak@linux.intel.com In-Reply-To: <1516310792-208685-18-git-send-email-kan.liang@intel.com> References: <1516310792-208685-18-git-send-email-kan.liang@intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf top: Check the latency of perf_top__mmap_read() Git-Commit-ID: 8cc42de736b617827a4e7664fb8d7a325bc125bc 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: 8cc42de736b617827a4e7664fb8d7a325bc125bc Gitweb: https://git.kernel.org/tip/8cc42de736b617827a4e7664fb8d7a325bc125bc Author: Kan Liang AuthorDate: Thu, 18 Jan 2018 13:26:32 -0800 Committer: Arnaldo Carvalho de Melo CommitDate: Thu, 15 Feb 2018 09:57:06 -0300 perf top: Check the latency of perf_top__mmap_read() The latency of perf_top__mmap_read() should be lower than refresh time. If not, give some hints to reduce the latency. Signed-off-by: Kan Liang Acked-by: Jiri Olsa Cc: Andi Kleen Cc: Jin Yao Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1516310792-208685-18-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-top.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c index 2b4914f..b7c823b 100644 --- a/tools/perf/builtin-top.c +++ b/tools/perf/builtin-top.c @@ -889,8 +889,10 @@ static void perf_top__mmap_read(struct perf_top *top) { bool overwrite = top->record_opts.overwrite; struct perf_evlist *evlist = top->evlist; + unsigned long long start, end; int i; + start = rdclock(); if (overwrite) perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_DATA_PENDING); @@ -901,6 +903,13 @@ static void perf_top__mmap_read(struct perf_top *top) perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_EMPTY); perf_evlist__toggle_bkw_mmap(evlist, BKW_MMAP_RUNNING); } + end = rdclock(); + + if ((end - start) > (unsigned long long)top->delay_secs * NSEC_PER_SEC) + ui__warning("Too slow to read ring buffer.\n" + "Please try increasing the period (-c) or\n" + "decreasing the freq (-F) or\n" + "limiting the number of CPUs (-C)\n"); } /*