From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from MailerDaemon by bender.weihenstephan.org with local-bsmtp (Exim 4.63) (envelope-from ) id 1IQPiB-0005MY-6l for linux-mm@kvack.org; Wed, 29 Aug 2007 17:44:07 +0200 From: Juergen Beisert Subject: Re: speeding up swapoff Date: Wed, 29 Aug 2007 17:12:35 +0200 References: <1188394172.22156.67.camel@localhost> <20070829073040.1ec35176@laptopd505.fenrus.org> <1188398683.22156.77.camel@localhost> In-Reply-To: <1188398683.22156.77.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200708291712.35967.juergen127@kreuzholzen.de> Sender: owner-linux-mm@kvack.org Return-Path: To: linux-kernel@vger.kernel.org Cc: Daniel Drake , Arjan van de Ven , linux-mm@kvack.org List-ID: On Wednesday 29 August 2007 16:44, Daniel Drake wrote: > On Wed, 2007-08-29 at 07:30 -0700, Arjan van de Ven wrote: > > > My experiments show that when there is not much free physical memory, > > > swapoff moves pages out of swap at a rate of approximately 5mb/sec. > > > > sounds like about disk speed (at random-seek IO pattern) > > We are only using 'standard' seagate SATA disks, but I would have > thought much more performance (40+ mb/sec) would be reachable. > > > before you go there... is this a "real life" problem? Or just a > > mostly-artificial corner case? (the answer to that obviously is > > relevant for the 'should we really care' question) > > It's more-or-less a real life problem. We have an interactive > application which, when triggered by the user, performs rendering tasks > which must operate in real-time. In attempt to secure performance, we > want to ensure everything is memory resident and that nothing might be > swapped out during the process. So, we run swapoff at that time. Did you play with mlock()? Juergen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org