Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932691AbVLHWus (ORCPT ); Thu, 8 Dec 2005 17:50:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932693AbVLHWus (ORCPT ); Thu, 8 Dec 2005 17:50:48 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:51910 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S932691AbVLHWur (ORCPT ); Thu, 8 Dec 2005 17:50:47 -0500 Date: Thu, 8 Dec 2005 23:50:28 +0100 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andy Isaacson , Nigel Cunningham , Linux Kernel Mailing List Subject: Re: swsusp performance problems in 2.6.15-rc3-mm1 Message-ID: <20051208225027.GA3970@elf.ucw.cz> References: <20051205081935.GI22168@hexapodia.org> <200512071217.41814.rjw@sisk.pl> <20051207113003.GD2563@elf.ucw.cz> <200512082342.38759.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200512082342.38759.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1326 Lines: 33 Hi! > > > Let me explain what I have in mind. > > > > > > For starters, please observe that the addresses we use are page-aligned, > > > so the least significant bit is always zero. Thus it can be used as a marker. > > > > > > Now before we save the image we can mark blank pages by setting > > > the least significant bit of .orig_address to 1 in the coresponding PBEs. > > > We save the "marked" .orig_address values to the image. > > > > Well, nice optimalization, but how many pages are actually full of > > zeros? > > According to the results I have obtained, there are about 1000 such > pages in the image on my box, for total image sizes between 28000 > and 80000 pages (ie above 28000 of pages in the image the number > of blank pages is almost constant). 4MB of zeros. I'd say that ewe have bigger problems to solve. Detecting zero pages is actually very trivial form of compression, and I think that we might as well do it properly, and use something like LZW -- if we want to go that way. I think that should be userspace problem. Pavel -- Thanks, Sharp! - 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/