Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750717AbVJJIp6 (ORCPT ); Mon, 10 Oct 2005 04:45:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750723AbVJJIp6 (ORCPT ); Mon, 10 Oct 2005 04:45:58 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:47325 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S1750717AbVJJIp6 (ORCPT ); Mon, 10 Oct 2005 04:45:58 -0400 Date: Mon, 10 Oct 2005 10:45:35 +0200 From: Pavel Machek To: OBATA Noboru Cc: hyoshiok@miraclelinux.com, linux-kernel@vger.kernel.org Subject: Re: Linux Kernel Dump Summit 2005 Message-ID: <20051010084535.GA2298@elf.ucw.cz> References: <20050921.205550.927509530.hyoshiok@miraclelinux.com> <20051006.211718.74749573.noboru.obata.ar@hitachi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20051006.211718.74749573.noboru.obata.ar@hitachi.com> 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: 1534 Lines: 42 Hi! > FULL DUMP WITH COMPRESSION > ========================== > > Those who still want a full dump, including me, are interested > in dump compression. For example, the LKCD format (at least v7 > format) supports pagewise compression with the deflate > algorithm. A dump analyze tool "crash" can transparently > analyze the compressed dump file in this format. > > The compression will reduce the storage space at certain degree, > and may also reduce the time if a dump process were I/O bounded. I'd say that compression does not help much, it can only speed it up twice. But... > > WHICH IS BETTER? > ================ > > I wrote a small compression tool for LKCD v7 format to see how > effective the compression is, and it turned out that the time > and size of compression were very much similar to that of gzip, > not surprisingly. > > Compressing a 32GB dump file took about 40 minutes on Pentium 4 > Xeon 3.0GHz, which is not good enough because the dump without > compression took only 5 minutes; eight times slower. ....you probably want to look at suspend2.net project. They have special compressor aimed at compressing exactly this kind of data, fast enough to be improvement. Pavel -- if you have sharp zaurus hardware you don't need... you know my address - 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/