From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753307Ab1GWSia (ORCPT ); Sat, 23 Jul 2011 14:38:30 -0400 Received: from mx2.fusionio.com ([66.114.96.31]:54963 "EHLO mx2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753188Ab1GWSi1 (ORCPT ); Sat, 23 Jul 2011 14:38:27 -0400 X-ASG-Debug-ID: 1311446304-01de280c1eeac60001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4E2B151C.6080900@fusionio.com> Date: Sat, 23 Jul 2011 20:38:20 +0200 From: Jens Axboe MIME-Version: 1.0 To: Christoph Hellwig CC: Dan Williams , Roland Dreier , Dave Jiang , "linux-kernel@vger.kernel.org" , "linux-scsi@vger.kernel.org" Subject: Re: [RFC PATCH 1/2] block: strict rq_affinity References: <20110722205736.17420.41366.stgit@localhost6.localdomain6> <20110722205938.17420.68621.stgit@localhost6.localdomain6> <20110723014633.GA32507@infradead.org> X-ASG-Orig-Subj: Re: [RFC PATCH 1/2] block: strict rq_affinity In-Reply-To: <20110723014633.GA32507@infradead.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1311446304 X-Barracuda-URL: http://10.101.1.181:8000/cgi-mod/mark.cgi X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using global 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 3.2.2.69773 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 2011-07-23 03:46, Christoph Hellwig wrote: > On Fri, Jul 22, 2011 at 01:59:39PM -0700, Dan Williams wrote: >> Some storage controllers benefit from completions always being steered >> to the strict requester cpu rather than the looser "per-socket" steering >> that blk_cpu_to_group() attempts by default. > > Isn't this actually dependent on the cpu, and not the storage > controller? It is, it's completely indendent of the controller used. Perhaps some drivers could have a very heavy end io completion handling causing the problem to become larger, but in general it's an artifact of the CPU and not the controller. -- Jens Axboe