From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752226Ab1HXN7N (ORCPT ); Wed, 24 Aug 2011 09:59:13 -0400 Received: from mx1.fusionio.com ([66.114.96.30]:38250 "EHLO mx1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129Ab1HXN7K (ORCPT ); Wed, 24 Aug 2011 09:59:10 -0400 X-ASG-Debug-ID: 1314194349-03d6a50f46302c0001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4E5503AA.3010908@fusionio.com> Date: Wed, 24 Aug 2011 15:59:06 +0200 From: Jens Axboe MIME-Version: 1.0 To: Shaohua Li CC: lkml Subject: Re: [patch 1/2]block: change force plug flush call order References: <1314176129.29510.34.camel@sli10-conroe> X-ASG-Orig-Subj: Re: [patch 1/2]block: change force plug flush call order In-Reply-To: <1314176129.29510.34.camel@sli10-conroe> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1314194349 X-Barracuda-URL: http://10.101.1.180:8000/cgi-mod/mark.cgi X-Barracuda-Bayes: INNOCENT GLOBAL 0.0000 1.0000 -2.0210 X-Barracuda-Spam-Score: -2.02 X-Barracuda-Spam-Status: No, SCORE=-2.02 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.72697 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-08-24 10:55, Shaohua Li wrote: > Do blk_flush_plug_list() first and then add new request at the tail. New > request can't be merged to existing requests, but later new requests might > be merged with this new one. If blk_flush_plug_list() is done later, the > merge doesn't happen. > Believe it or not, this fixes a 10% regression running sysbench workload. Heh, funky. But conceptually it makes sense to flush first, since we already know that this request isn't mergeable already. Applied. -- Jens Axboe