From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934495AbXEWPH5 (ORCPT ); Wed, 23 May 2007 11:07:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756509AbXEWPHt (ORCPT ); Wed, 23 May 2007 11:07:49 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:15466 "EHLO viefep34-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755863AbXEWPHt (ORCPT ); Wed, 23 May 2007 11:07:49 -0400 Subject: Re: [PATCH 3/7] lockdep: lock contention tracking From: Peter Zijlstra To: Jason Baron Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Bill Huey , Steven Rostedt , Christoph Hellwig In-Reply-To: References: <20070523072618.129001605@chello.nl> <20070523095807.407148940@chello.nl> Content-Type: text/plain Date: Wed, 23 May 2007 17:07:45 +0200 Message-Id: <1179932865.7019.90.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-05-23 at 10:40 -0400, Jason Baron wrote: > On Wed, 23 May 2007, Peter Zijlstra wrote: > > > Count lock contention events per lock class. Additionally track the first four > > callsites that resulted in the contention. > > > > I think that we need the total number of locking calls, not just the total > number of *contended* locking calls, in order to make the data > significant. Same for waittime. Yes, this pollutes the fastpath. In the > contention case, its one extra addition, and for the waittime, its a call > the sched_clock(). I don't think that's too much to pay for much more > meaningful data. The holdtime statistics add these numbers.