From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [RFC PATCH 0/4] dm mpath: vastly improve blk-mq IO performance Date: Fri, 1 Apr 2016 09:22:19 -0400 Message-ID: <20160401132219.GA24355@redhat.com> References: <1459454666-76428-1-git-send-email-snitzer@redhat.com> <6c6623e7f92e31daf1586d266fa03e1d@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mx1.redhat.com ([209.132.183.28]:34837 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750751AbcDANWV (ORCPT ); Fri, 1 Apr 2016 09:22:21 -0400 Content-Disposition: inline In-Reply-To: <6c6623e7f92e31daf1586d266fa03e1d@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Johannes Thumshirn Cc: dm-devel@redhat.com, linux-scsi@vger.kernel.org, sagig@dev.mellanox.co.il, linux-block@vger.kernel.org, jmoyer@redhat.com, j-nomura@ce.jp.nec.com On Fri, Apr 01 2016 at 4:12am -0400, Johannes Thumshirn wrote: > On 2016-03-31 22:04, Mike Snitzer wrote: > >I developed these changes some weeks ago but have since focused on > >regression and performance testing on larger NUMA systems. > > > >For regression testing I've been using mptest: > >https://github.com/snitm/mptest > > > >For performance testing I've been using a null_blk device (with > >various configuration permutations, e.g. pinning memory to a > >particular NUMA node, and varied number of submit_queues). > > > >By eliminating multipath's heavy use of the m->lock spinlock in the > >fast IO paths serious performance improvements are realized. > > Hi Mike, > > Are this the patches you pointed Hannes to? > > If yes, please add my Tested-by: Johannes Thumshirn No they are not. Hannes seems to have last pulled in my DM mpath changes that (ab)used RCU. I ended up dropping those changes and this patchset is the replacement. So please retest with this patchset (I know you guys have a large setup that these changes are very relevant for). If you could actually share _how_ yo've tested that'd help me understand how these changes are holding up. So far all looks good for me... Mike