Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262226AbVD1Se5 (ORCPT ); Thu, 28 Apr 2005 14:34:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262224AbVD1Se5 (ORCPT ); Thu, 28 Apr 2005 14:34:57 -0400 Received: from e31.co.us.ibm.com ([32.97.110.129]:8664 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S262222AbVD1Seg (ORCPT ); Thu, 28 Apr 2005 14:34:36 -0400 Subject: Re: [RFC][PATCH] Reduce ext3 allocate-with-reservation lock latencies From: Mingming Cao Reply-To: cmm@us.ibm.com To: Lee Revell Cc: Andrew Morton , "Stephen C. Tweedie" , Ingo Molnar , linux-kernel In-Reply-To: <1114704726.17712.17.camel@mindpipe> References: <1112673094.14322.10.camel@mindpipe> <20050405041359.GA17265@elte.hu> <1112765751.3874.14.camel@localhost.localdomain> <20050407081434.GA28008@elte.hu> <1112879303.2859.78.camel@sisko.sctweedie.blueyonder.co.uk> <1112917023.3787.75.camel@dyn318043bld.beaverton.ibm.com> <1112971236.1975.104.camel@sisko.sctweedie.blueyonder.co.uk> <1112983801.10605.32.camel@dyn318043bld.beaverton.ibm.com> <1113220089.2164.52.camel@sisko.sctweedie.blueyonder.co.uk> <1113244710.4413.38.camel@localhost.localdomain> <1113249435.2164.198.camel@sisko.sctweedie.blueyonder.co.uk> <1113288087.4319.49.camel@localhost.localdomain> <1113304715.2404.39.camel@sisko.sctweedie.blueyonder.co.uk> <1113348434.4125.54.camel@dyn318043bld.beaverton.ibm.com> <1113388142.3019.12.camel@sisko.sctweedie.blueyonder.co.uk> <1114207837.7339.50.camel@localhost.localdomain> <1114659912.16933.5.camel@mindpipe> <1114673852.4104.33.camel@localhost.localdomain> <1114704726.17712.17.camel@mindpipe> Content-Type: text/plain Organization: IBM LTC Date: Thu, 28 Apr 2005 11:34:18 -0700 Message-Id: <1114713258.18996.7.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-3) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1468 Lines: 34 On Thu, 2005-04-28 at 12:12 -0400, Lee Revell wrote: > On Thu, 2005-04-28 at 00:37 -0700, Mingming Cao wrote: > > On Wed, 2005-04-27 at 23:45 -0400, Lee Revell wrote: > > > On Fri, 2005-04-22 at 15:10 -0700, Mingming Cao wrote: > > > > Please review. I have tested on fsx on SMP box. Lee, if you got time, > > > > please try this patch. > > > > > > I have tested and this does fix the problem. I ran my tests and no ext3 > > > code paths showed up on the latency tracer at all, it never went above > > > 33 usecs. > > > > > Thanks, Lee. > > > > The patch survived on many fsx test over 20 hours on a 2cpu machine. > > Tested the patch on the same machine with tiobench (1-64 threads), and > > untar a kernel tree test, no regression there. > > However I see about 5-7% throughput drop on dbench with 16 threads. It > > probably due to the cpu cost that we have discussed. > > Hmm, I guess someone needs to test it on a bigger system. AFAICT this > should improve SMP scalability quite a bit. Maybe that lock is rarely > contended. Probably. I will try it on a relatively full filesystem(where bitmap scan to find a free block takes time), and on a 4 cpu box with many threads allocating at the same time. Mingming - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/