Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 26 Sep 2002 04:22:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 26 Sep 2002 04:22:49 -0400 Received: from m029-045.nv.iinet.net.au ([203.217.29.45]:20363 "EHLO localhost") by vger.kernel.org with ESMTP id ; Thu, 26 Sep 2002 04:22:49 -0400 To: Jens Axboe Cc: Linux Kernel Subject: Re: [PATCH] deadline io scheduler References: <20020925172024.GH15479@suse.de> <3D92A61E.40BFF2D0@digeo.com> <20020926064455.GC12862@suse.de> In-Reply-To: <20020926064455.GC12862@suse.de> (Jens Axboe's message of "Thu, 26 Sep 2002 08:44:55 +0200") From: Daniel Pittman Organization: Not today, thank you, Mother. Date: Thu, 26 Sep 2002 18:28:01 +1000 Message-ID: <87k7l95f5a.fsf@enki.rimspace.net> User-Agent: Gnus/5.090006 (Oort Gnus v0.06) XEmacs/21.5 (bamboo, i686-pc-linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1372 Lines: 30 On Thu, 26 Sep 2002, Jens Axboe wrote: > On Wed, Sep 25 2002, Andrew Morton wrote: [...] > writes_starved. This controls how many times reads get preferred over > writes. The default is 2, which means that we can serve two batches of > reads over one write batch. A value of 4 would mean that reads could > skip ahead of writes 4 times. A value of 1 would give you 1:1 > read:write, ie no read preference. A silly value of 0 would give you > write preference, always. Actually, a value of zero doesn't sound completely silly to me, right now, since I have been doing a lot of thinking about video capture recently. How much is it going to hurt a filesystem like ext[23] if that value is set to zero while doing large streaming writes -- something like (almost) uncompressed video at ten to twenty meg a second, for gigabytes? This is a situation where, for a dedicated machine, delaying reads almost forever is actually a valuable thing. At least, valuable until it stops the writes from being able to proceed. Daniel -- The best way to get a bad law repealed is to enforce it strictly. -- Abraham Lincoln - 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/