From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arun Sharma Subject: Re: [Devel] [PATCH 0/7] Profiling sleep times (v3) Date: Wed, 7 Dec 2011 12:33:48 -0800 Message-ID: <4EDFCDAC.3060600@fb.com> References: <1322471015-107825-1-git-send-email-avagin@openvz.org> <4EDDC0FB.6080005@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset="KOI8-R"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4EDDC0FB.6080005@openvz.org> Sender: linux-kernel-owner@vger.kernel.org To: avagin@openvz.org Cc: Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org, Peter Zijlstra , linux-perf-users@vger.kernel.org, Paul Mackerras , devel@openvz.org, David Ahern , Ingo Molnar List-Id: linux-perf-users.vger.kernel.org On 12/5/11 11:15 PM, Andrey Vagin wrote: > Arun Sharma said, that the second versions of patches works ok for him. > (Arun is the first user of this functionality after me.) Yes - Andrey's patches (v2) have been functional for me when used via: perf record -agP -e sched:sched_switch --filter "prev_state == 1 || prev_state == 2" -e sched:sched_stat_sleep,sched:sched_stat_iowait -- sleep 3 mv perf.data{,.old}; perf inject -s -i perf.data.old -o perf.data perf report --stdio -g graph --sort pid -C command-name There are two major issues though: * The above command lines cause us to collect way too much data and perf can't keep up on a busy server Eg: Warning: Processed 55182 events and lost 13 chunks! Check IO/CPU overload! * Requires root access I suspect there is a way to stash the delay information available at enqueue_sleeper() into the task_struct (or some place else) and make it available at the sched:sched_switch tracepoint. This would solve both of the problems above, but I don't have a patch yet. -Arun