From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.62) (envelope-from ) id 1HmGP7-0006u9-Qg for garchives@archives.gentoo.org; Thu, 10 May 2007 21:42:30 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.14.0/8.14.0) with SMTP id l4ALfCev006432; Thu, 10 May 2007 21:41:12 GMT Received: from spore.ath.cx (c-24-245-14-14.hsd1.mn.comcast.net [24.245.14.14]) by robin.gentoo.org (8.14.0/8.14.0) with ESMTP id l4ALa3dH032713 for ; Thu, 10 May 2007 21:36:04 GMT Received: from pascal.spore.ath.cx (pascal.spore.ath.cx [192.168.1.100]) by spore.ath.cx (Postfix) with ESMTP id 9D3421D6D0 for ; Thu, 10 May 2007 16:36:03 -0500 (CDT) Date: Thu, 10 May 2007 16:36:03 -0500 From: Dan Farrell To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: Separate /usr Message-ID: <20070510163603.5d3836e4@pascal.spore.ath.cx> In-Reply-To: <20070510113446.7fdae1b8@hactar.digimed.co.uk> References: <49bf44f10705081656s776f28f5kbe497a5326107c2f@mail.gmail.com> <3103632.vvIsoWeEWl@kn.gn.rtr.message-center.info> <20070510104016.360d3a97@hactar.digimed.co.uk> <200705101211.34696.benno.schulenberg@gmail.com> <20070510113446.7fdae1b8@hactar.digimed.co.uk> Organization: Spore, Ltd. X-Mailer: Claws Mail 2.6.1 (GTK+ 2.10.6; x86_64-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Archives-Salt: 8432c989-75e1-4723-bbd4-2c88c6378851 X-Archives-Hash: e26f577ea2eacbfceaa281e72cdf5a5a On Thu, 10 May 2007 11:34:46 +0100 Neil Bothwick wrote: > On Thu, 10 May 2007 12:11:34 +0200, Benno Schulenberg wrote: > > > > No idea, but I tried it when I encountered that page and portage > > > operations were measurably faster. > > > > That might well be just the transfer effect: you went from an old > > fragmented file system to a fresh unfragmented one. > > I allowed for that. I created a new filesystem for /usr/portage - I > had been using a directory in /usr before. > > Well, maybe it has to do with the efficiency of reading discontiguous blocks from one file as opposed to a filesystem. Since it's a sparse file, there might be a lot of 'space' that, if it were on an actual disk, the heads would have to pass over; thus there may be a way in which a sparse file is more efficient than a regular filesystem. Remeber that the files in portage are, except for distfiles, quite small. By my calculation, the average size for files and directories under $PORTDIR (excluding $DISTDIR of course) is only 62 bytes. What would you bet that on a disk partition, the other 962 to 4034 bytes per block (I couldn't have block sizes less than 1K on reiser for my portage, and 4096 is the default for most FS's) are filled with nothing, and the heads need to pass over them to read the next block. On a sparse file that space is merely reserved, it needn't actually exist. Hope that helps you conceptualize the difference. -- gentoo-user@gentoo.org mailing list