From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: [RFC] VM: I have a dream... Date: Mon, 23 Jan 2006 13:17:07 +0000 Message-ID: <20060123131707.GA20163@mail.shareable.org> References: <200601212108.41269.a1426z@gawab.com> <986ed62e0601221155x6a57e353vf14db02cc219c09@mail.gmail.com> <200601222346.24781.chase.venters@clientec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Michael Loftis , "Barry K. Nathan" , Al Boldi , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: Received: from mail.shareable.org ([81.29.64.88]:50824 "EHLO mail.shareable.org") by vger.kernel.org with ESMTP id S1751438AbWAWNRO (ORCPT ); Mon, 23 Jan 2006 08:17:14 -0500 To: Chase Venters Content-Disposition: inline In-Reply-To: <200601222346.24781.chase.venters@clientec.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Chase Venters wrote: > Just as a curiosity... does anyone have any guesses as to the > runtime performance cost of hosting one or more swap files (which > thanks to on demand creation and growth are presumably built of > blocks scattered around the disk) versus having one or more simple > contiguous swap partitions? > I think it's probably a given that swap partitions are better; I'm just > curious how much better they might actually be. When programs must access files in addition to swapping, and that includes demand-paged executable files, swap files have the _potential_ to be faster because they provide opportunities to use the disk nearer the files which are being accessed. This is more so is all the filesystem's free space is available for swapping. A swap partition in this scenario forces the disk head to move back and forth between the swap partition and the filesystem. -- Jamie