Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752512AbZCPFNP (ORCPT ); Mon, 16 Mar 2009 01:13:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751898AbZCPFM6 (ORCPT ); Mon, 16 Mar 2009 01:12:58 -0400 Received: from mga11.intel.com ([192.55.52.93]:51745 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751538AbZCPFM5 (ORCPT ); Mon, 16 Mar 2009 01:12:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.38,371,1233561600"; d="scan'208";a="673188304" Subject: Re: [Bug #12809] iozone regression with 2.6.29-rc6 From: Lin Ming To: Linus Torvalds Cc: "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Andrew Morton , Nick Piggin , Peter Zijlstra , "Wu, Fengguang" In-Reply-To: References: Content-Type: text/plain Date: Mon, 16 Mar 2009 13:03:42 +0800 Message-Id: <1237179822.27907.6.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 (2.24.1-2.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1853 Lines: 45 On Sun, 2009-03-15 at 08:27 +0800, Linus Torvalds wrote: > > On Sat, 14 Mar 2009, Rafael J. Wysocki wrote: > > > > The following bug entry is on the current list of known regressions > > from 2.6.28. Please verify if it still should be listed and let me know > > (either way). > > > > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12809 > > Subject : iozone regression with 2.6.29-rc6 > > Submitter : Lin Ming > > Date : 2009-02-27 9:13 (16 days old) > > First-Bad-Commit: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=1cf6e7d83bf334cc5916137862c920a97aabc018 > > References : http://marc.info/?l=linux-kernel&m=123572630504360&w=4 > > Handled-By : Wu Fengguang > > I suspect that I should just raise the default dirty limits. Wu reported > that it fixed the regression, and while he picked some rather high > percentages, I think we could certainly raise the rather aggressive > default ones. > > After all, those default percentages were picked (a) with the old dirty > logic and (b) largely at random and (c) designed to be aggressive. In > particular, that (a) means that having fixed some of the dirty accounting, > maybe the real bug is now that it was always too aggressive, just hidden > by an accounting issue. > > If we raised the default ratio from 5/10 to 10/20, what happens to the > iozone regression? echo 10 > /proc/sys/vm/dirty_background_ratio echo 20 > /proc/sys/vm/dirty_ratio It fixed the regression of iozone (filesize 1200M) on 4P dual-core HT machine(8G mem). Lin Ming -- 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/