From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932734AbXA1SDG (ORCPT ); Sun, 28 Jan 2007 13:03:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752472AbXA1SDG (ORCPT ); Sun, 28 Jan 2007 13:03:06 -0500 Received: from adsl-69-232-92-238.dsl.sndg02.pacbell.net ([69.232.92.238]:58332 "EHLO gnuppy.monkey.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752474AbXA1SDF (ORCPT ); Sun, 28 Jan 2007 13:03:05 -0500 Date: Sun, 28 Jan 2007 10:01:32 -0800 To: "Martin J. Bligh" Cc: Christoph Hellwig , Ingo Molnar , Peter Zijlstra , Andrew Morton , linux-kernel@vger.kernel.org, Dipankar Sarma , "Bill Huey (hui)" Subject: Re: lockmeter Message-ID: <20070128180132.GA1647@gnuppy.monkey.org> References: <20070128115118.837777000@programming.kicks-ass.net> <20070128144325.GB16552@infradead.org> <20070128152404.GB9196@elte.hu> <45BCD4C9.2030302@mbligh.org> <20070128170407.GA1526@infradead.org> <45BCDF88.2020504@mbligh.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45BCDF88.2020504@mbligh.org> User-Agent: Mutt/1.5.13 (2006-08-11) From: Bill Huey (hui) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 28, 2007 at 09:38:16AM -0800, Martin J. Bligh wrote: > Christoph Hellwig wrote: > >On Sun, Jan 28, 2007 at 08:52:25AM -0800, Martin J. Bligh wrote: > >>Mmm. not wholly convinced that's true. Whilst i don't have lockmeter > >>stats to hand, the heavy time in __d_lookup seems to indicate we may > >>still have a problem to me. I guess we could move the spinlocks out > >>of line again to test this fairly easily (or get lockmeter upstream). > > > >We definitly should get lockmeter in. Does anyone volunteer for doing > >the cleanup and merged? > > On second thoughts .. I don't think it'd actually work for this since > the locks aren't global. Not that it shouldn't be done anyway, but ... > > ISTR we still thought dcache scalability was a significant problem last > time anyone looked at it seriously - just never got fixed. Dipankar? My lock stat stuff shows dcache to a be a problem under -rt as well. It is keyed off the same mechanism as lockdep. It's pretty heavily hit under even normal loads relative to other kinds of lock overhead even for casual file operations on a 2x system. I can't imagine how lousy it's going to be under real load on a 8x or higher machine. However, this pathc is -rt only and spinlock times are meaningless under it because of preemptiblity. bill