From: Ingo Molnar Subject: Re: [BUG] Strange 1-second pauses during Resume-from-RAM Date: Sun, 2 Dec 2007 21:45:59 +0100 Message-ID: <20071202204559.GA28550@elte.hu> References: <20071201205456.GA8231@elte.hu> <20071201234112.GA7209@lazybastard.org> <20071202085607.GA28966@elte.hu> <20071202113143.GA9378@lazybastard.org> <20071202135711.GA20434@elte.hu> <20071202141117.GB9516@lazybastard.org> <20071202154746.GA27069@elte.hu> <20071202195501.GB10657@lazybastard.org> <20071202200722.GA12101@elte.hu> <20071202203016.GC10657@lazybastard.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <20071202203016.GC10657@lazybastard.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: =?iso-8859-1?Q?J=F6rn?= Engel Cc: len.brown@intel.com, linux-kernel@vger.kernel.org, Mark Lord , Mark Lord , Thomas Gleixner , linux-pm@lists.linux-foundation.org, Andrew Morton List-Id: linux-pm@vger.kernel.org * J=F6rn Engel wrote: > > oprofile helps if you can reliably reproduce the slowdown in a loop=20 > > or for a long amount of time, with lots of CPU utilization - and=20 > > then it's also lower overhead. The tracer can be used to capture=20 > > rare or complex events, and gives the full flow control and what is=20 > > happening within the kernel. >=20 > Such a trace would be useful indeed. But so far the patch has only=20 > given me grief and nothing remotely like useful output. Maybe I=20 > should simply use the complete -rt patch instead of debugging the=20 > broken-out latency-tracer patch. to capture that trace i did not use -rt, i just patched latest -git=20 with: http://people.redhat.com/mingo/latency-tracing-patches/latency-tracing-= v2.6.24-rc3.combo.patch (this has your fixes included already) have done: echo 1 > /proc/sys/kernel/mcount_enabled and have run: ./trace-cmd sleep 1 > trace.txt http://people.redhat.com/mingo/latency-tracing-patches/trace-cmd.c to capture a 1 second trace of what the system is doing. I think your=20 troubles are due to running it within a qemu guest - that is not a=20 typical utilization so you are on unchartered waters. Ingo