From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: [PATCH v3 00/18] periodic write-back timer optimization Date: Thu, 09 Jul 2009 14:37:57 +0200 Message-ID: <871voq6nh6.fsf@basil.nowhere.org> References: <20090709084822.12122.79749.sendpatchset@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Al Viro , Jens Axboe , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Artem Bityutskiy Return-path: Received: from one.firstfloor.org ([213.235.205.2]:47268 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757248AbZGIMh7 (ORCPT ); Thu, 9 Jul 2009 08:37:59 -0400 In-Reply-To: <20090709084822.12122.79749.sendpatchset@localhost.localdomain> (Artem Bityutskiy's message of "Thu, 09 Jul 2009 11:48:22 +0300") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Artem Bityutskiy writes: > > The patches attempt to optimize the periodic write-back and stop it when > there are no dirty data. IOW, we do not want the thread to wake up every > 5 seconds (by default), find there is nothing to do, and so on. Is waking up every 5 seconds really a problem? The normal rule of thumb is iirc that longer sleep times than a few hundred ms give dimishing returns in terms of power saving. A simple way might be simple to batch the timer better with other timers. -Andi -- ak@linux.intel.com -- Speaking for myself only.