Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262293AbTHTWwK (ORCPT ); Wed, 20 Aug 2003 18:52:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262309AbTHTWwK (ORCPT ); Wed, 20 Aug 2003 18:52:10 -0400 Received: from adsl-63-194-239-202.dsl.lsan03.pacbell.net ([63.194.239.202]:17162 "EHLO mmp-linux.matchmail.com") by vger.kernel.org with ESMTP id S262293AbTHTWwG (ORCPT ); Wed, 20 Aug 2003 18:52:06 -0400 Date: Wed, 20 Aug 2003 15:52:00 -0700 From: Mike Fedyk To: Jamie Lokier Cc: Denis Vlasenko , Sergey Spiridonov , linux-kernel@vger.kernel.org Subject: Re: how to turn off, or to clear read cache? Message-ID: <20030820225200.GB1040@matchmail.com> Mail-Followup-To: Jamie Lokier , Denis Vlasenko , Sergey Spiridonov , linux-kernel@vger.kernel.org References: <3F4360F0.209@gamic.com> <200308201311.h7KDBgL20530@Port.imtp.ilyichevsk.odessa.ua> <20030820224628.GA24639@mail.jlokier.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030820224628.GA24639@mail.jlokier.co.uk> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 24 On Wed, Aug 20, 2003 at 11:46:28PM +0100, Jamie Lokier wrote: > Denis Vlasenko wrote: > > On 20 August 2003 14:52, Sergey Spiridonov wrote: > > > I need to make some performance tests. I need to switch off or to clear > > > read cache, so that consequent reading of the same file will take the > > > same amount of time. > > > > umount/mount cycle will do it, as well as intentional OOMing the box > > (from non-root account please;) > > umount/mount is impractical when you're testing performance on a big > filesystem, which is always being used (e.g. /home). > > I'm fairly sure that -o remount used to have this side effect, in fact > I used it quite a lot for that purpose, so it should be possible to > make it work again, or add a -o flushcache option. Won't that hold a lot of locks, and possibly pause the system until the flushing is complete? Hopefully, in 2.6 this doesn't call lock_kernel... - 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/