From: Jens Axboe Subject: Re: [PATCH] block: Add a trace point whenever a barrier IO request is sent Date: Wed, 21 Apr 2010 23:27:27 +0200 Message-ID: <20100421212727.GY27497@kernel.dk> References: <20100421205626.GA15607@tux1.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel , linux-ext4 To: "Darrick J. Wong" Return-path: Received: from 0122700014.0.fullrate.dk ([95.166.99.235]:53281 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755812Ab0DUV13 (ORCPT ); Wed, 21 Apr 2010 17:27:29 -0400 Content-Disposition: inline In-Reply-To: <20100421205626.GA15607@tux1.beaverton.ibm.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Apr 21 2010, Darrick J. Wong wrote: > Simple debugging patch used to watch for barrier requests. I've been using > this to watch ext4's barrier=1 behavior. But barriers are already being logged, if you watch blkparse data, it'll be RB or WB events. So I don't see what this addition provides that we don't already have? -- Jens Axboe