From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262422AbVCSHJO (ORCPT ); Sat, 19 Mar 2005 02:09:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262424AbVCSHJO (ORCPT ); Sat, 19 Mar 2005 02:09:14 -0500 Received: from mx1.elte.hu ([157.181.1.137]:4825 "EHLO mx1.elte.hu") by vger.kernel.org with ESMTP id S262422AbVCSHJK (ORCPT ); Sat, 19 Mar 2005 02:09:10 -0500 Date: Sat, 19 Mar 2005 08:08:10 +0100 From: Ingo Molnar To: Lee Revell Cc: linux-kernel , Andrew Morton , "Jack O'Quin" Subject: Re: Latency tests with 2.6.12-rc1 Message-ID: <20050319070810.GA20059@elte.hu> References: <1111204984.12740.22.camel@mindpipe> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1111204984.12740.22.camel@mindpipe> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Lee Revell wrote: > I did the same quick latency tests with 2.6.12-rc1 that I posted about > for 2.6.11 a few weeks ago. > > 2.6.12-rc1 is significantly better than 2.6.11. Running JACK at 64 > frames (1.3 ms) works very well. I was not able to produce xruns even > with "dbench 64", which slows the system to a crawl. With 2.6.11, I > could easily produce xruns with much lighter loads. > > It would appear that the latency issues related to the 4 level page > tables merge have been resolved. great! The change in question is most likely the copy_page_range() fix that Hugh resurrected: ChangeSet 1.2037, 2005/03/08 09:26:46-08:00, hugh@veritas.com [PATCH] copy_pte_range latency fix Ingo's patch to reduce scheduling latencies, by checking for lockbreak in copy_page_range, was in the -VP and -mm patchsets some months ago; but got preempted by the 4level rework, and not reinstated since. Restore it now in copy_pte_range - which mercifully makes it easier. are the ext3 related latencies are gone as well - or are you working it around by not using data=ordered? Ingo