From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bart Van Assche Subject: Re: [PATCH/RESEND] scsi.mq: Added use_cmd_list flag in scsi_host to reduce lock contention Date: Fri, 22 Aug 2014 18:04:17 +0200 Message-ID: <53F76A01.7060806@acm.org> References: <201408201357.s7KDvDeL021549@palmhbs0.lsi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from sf2.bxl.stone.is ([5.134.1.239]:41791 "EHLO sf2.bxl.stone.is" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932098AbaHVQEq (ORCPT ); Fri, 22 Aug 2014 12:04:46 -0400 In-Reply-To: <201408201357.s7KDvDeL021549@palmhbs0.lsi.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Kashyap.Desai@avagotech.com, linux-scsi@vger.kernel.org, hch@infradead.org, elliott@hp.com, jbottomley@parallels.com, aacraid@adaptec.com On 08/20/14 15:54, Kashyap.Desai@avagotech.com wrote: > Comment provided by Bart Van and Chris H is addressed in this patch. > > Add use_cmd_list flag in scsi_host to indicate scs.mq stack > to keep track of cmd_list per sdev. > > Default behaviour is not to keep track of cmd_list per sdev, as this may introduce > lock contention. (overhead is more on multi-node NUMA.) > > Patch is tested using megaraid_sas driver with "use_cmd_list" value set to 1 and 0. > Added MAINTAINER of Adaptec to verify changes. > > Signed-off-by: Kashyap Desai Reviewed-by: Bart Van Assche