Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754770AbZFYNoi (ORCPT ); Thu, 25 Jun 2009 09:44:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751901AbZFYNob (ORCPT ); Thu, 25 Jun 2009 09:44:31 -0400 Received: from mailhost18.gawab.com ([66.220.20.18]:34613 "HELO info3.gawab.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751160AbZFYNob (ORCPT ); Thu, 25 Jun 2009 09:44:31 -0400 X-Trusted: Whitelisted From: Al Boldi To: Ralf Gross Subject: Re: io-scheduler tuning for better read/write ratio Date: Thu, 25 Jun 2009 16:45:40 +0300 User-Agent: KMail/1.5 Cc: linux-kernel@vger.kernel.org, fengguang.wu@intel.com References: <4A37CB2A.6010209@davidnewall.com> <200906241057.41227.a1426z@gawab.com> <20090625072641.GB16642@p15145560.pureserver.info> In-Reply-To: <20090625072641.GB16642@p15145560.pureserver.info> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200906251645.40705.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 815 Lines: 42 Ralf Gross wrote: > Al Boldi schrieb: > > Try changing /proc/sys/vm/dirty_ratio = 1 > > $cat /proc/sys/vm/dirty_ratio > 1 > > > $dstat -D md1 -d 5 > --dsk/md1-- > _read _writ > 18M 18M > 0 0 > 820k 101M > 18M 113M > 26M 73M > 26M 110M > 32M 100M > 19M 111M > 13M 117M > 13M 142M > 32M 88M > 26M 99M > 38M 58M > > No change. Even setting dirty_ratio to 100 didn't show any difference. What's your readahead? Do a blockdev --getra /dev/sdX and /dev/mdX. Try increasing it, while keeping dirty_ratio low. Thanks! -- Al -- 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/