From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755519AbaCCXXV (ORCPT ); Mon, 3 Mar 2014 18:23:21 -0500 Received: from ipmail05.adl6.internode.on.net ([150.101.137.143]:27402 "EHLO ipmail05.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755182AbaCCXXU (ORCPT ); Mon, 3 Mar 2014 18:23:20 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Ao1uAPQNFVN5LJYePGdsb2JhbABagwaDQ4UMs0mFWYEeFwMBAQEBHxkNKIIlAQEFOhwjEAgDGAklDwUlAwcaE4d4zGYXFo5DB4MkgRQBA5g7ilWLGCg Date: Tue, 4 Mar 2014 10:17:40 +1100 From: Dave Chinner To: Fengguang Wu Cc: Dave Chinner , linux-fsdevel@vger.kernel.org, LKML Subject: Re: [xfs] f876e446: +1.2% fileio.requests_per_sec Message-ID: <20140303231740.GA6851@dastard> References: <20140303142151.GA7935@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140303142151.GA7935@localhost> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 03, 2014 at 10:21:51PM +0800, Fengguang Wu wrote: > Hi Dave, > > We noticed the below changes on commit f876e44603ad091c840a5fae5b0753bbb421c037 > ("xfs: always do log forces via the workqueue"): > > Basically there are +1.2% increased throughput with +29.5% increased > context switches. Yes, the increase in context switches is expected. Every sync IO causes a log force if it changed inode metadata, and the above commit, as it describes, moves them to a work queue. Hence there's more context switches involved in a log force that has to do work. Cheers, Dave. -- Dave Chinner david@fromorbit.com