From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Lei Subject: Re: [PATCH 0/2] block/SCSI MQ: two RESTART related patches Date: Tue, 17 Oct 2017 13:12:10 +0800 Message-ID: <20171017051209.GF15996@ming.t460p> References: <20171017050418.22555-1-ming.lei@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20171017050418.22555-1-ming.lei@redhat.com> Sender: linux-block-owner@vger.kernel.org To: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig Cc: Bart Van Assche , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Omar Sandoval , John Garry List-Id: linux-scsi@vger.kernel.org On Tue, Oct 17, 2017 at 01:04:16PM +0800, Ming Lei wrote: > Hi Jens, > > The 1st patch runs idle hctx after dealy in scsi_mq_get_budget(), > so that we can keep same behaviour with before, and it can be > thought as a fix. > > The 2nd patch cleans up RESTART, and removes handling for TAG_SHARED > from current blk-mq's RESTART mechanism because SCSI_MQ can covers its > restart by itself, so that no need to handle TAG_SHARED in blk-mq > RESTART. And >20% IOPS boost is observed in my rand read test over > scsi_debug. > > John, please test this two patches and see if it may improve your SAS > IO performance, and you can find the two patches in the following branch: > > https://github.com/ming1/linux/commits/blk_mq_improve_restart_V1 Forget to mention, you need to either pull the above branch directly or apply the two patches against for-next branch of Jens' block tree: git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git #for-next -- Ming