From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Olsa Subject: Re: perf lock usage Date: Thu, 30 Jan 2014 11:33:52 +0100 Message-ID: <20140130103352.GA1161@krava.brq.redhat.com> References: <21216.48020.60857.22056@gargle.gargle.HOWL> <20140128093542.GD1229@krava.brq.redhat.com> <21225.2037.467035.833797@gargle.gargle.HOWL> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12361 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751027AbaA3Kd6 (ORCPT ); Thu, 30 Jan 2014 05:33:58 -0500 Content-Disposition: inline In-Reply-To: <21225.2037.467035.833797@gargle.gargle.HOWL> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Sujith Manoharan Cc: linux-perf-users@vger.kernel.org On Wed, Jan 29, 2014 at 07:23:57PM +0530, Sujith Manoharan wrote: > Jiri Olsa wrote: > > some of the kernel lock types do not follow the: > > acquire > > contended > > acuired > > release > > > > lock state machine, like rcu or spin locks.. and thats what > > caused most of the bad rates in my tests. > > > > I was recently working on some changes for lock tracing, > > what stats are you interested in? > > I am trying to see lock usage stats for the ath9k wireless driver. > Mainly in the transmission path, where normal spin locks > are acquired. I was using following code for studying the lock flow, but it can also display the overhead (but not much in detail) git tree: git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git perf/core_lock branch the usage is sort of described in example here: https://git.kernel.org/cgit/linux/kernel/git/jolsa/perf.git/commit/?h=perf/core_lock&id=f140425e46b2469b825c12b72507c6f3c539c7dd so far I've been using the list mode only for checking the lock flow, but it doesn't seem much useful otherwise.. so I haven't shared it yet not sure this can be any use for you, but let me know if you'd need other info jirka