From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH] fs-writeback: drop wb->list_lock during blk_finish_plug() Date: Mon, 14 Sep 2015 08:56:50 +1000 Message-ID: <20150913225650.GR26895@dastard> References: <55F33C2B.1010508@fb.com> <20150911231636.GC4150@ret.masoncoding.com> <20150912230027.GE4150@ret.masoncoding.com> <20150912234632.GF4150@ret.masoncoding.com> <20150913131244.GA15926@ret.masoncoding.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Chris Mason , Linus Torvalds , Josef Bacik , LKML , linux-fsdevel , Neil Brown , Jan Kara , Christoph Hellwig Return-path: Content-Disposition: inline In-Reply-To: <20150913131244.GA15926@ret.masoncoding.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Sun, Sep 13, 2015 at 09:12:44AM -0400, Chris Mason wrote: > On Sat, Sep 12, 2015 at 07:46:32PM -0400, Chris Mason wrote: > > I don't think the XFS numbers can be trusted too much since it was > > basically bottlenecked behind that single pegged CPU. It was bouncing > > around and I couldn't quite track it down to a process name (or perf > > profile). > > I'll do more runs Monday, but I was able to grab a perf profile of the > pegged XFS CPU. It was just the writeback worker thread, and it > hit btrfs differently because we defer more of this stuff to endio > workers, effectively spreading it out over more CPUs. > > With 4 mount points intead of 2, XFS goes from 140K files/sec to 250K. > Here's one of the profiles, but it bounced around a lot so I wouldn't > use this to actually tune anything: mkfs.xfs -d agcount=64 .... Cheers, Dave. -- Dave Chinner david@fromorbit.com