From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: Hot rb_next, setup_cluster_no_bitmap Date: Wed, 03 Aug 2011 21:13:26 -0400 Message-ID: <1312420323-sup-5706@shiny> References: <20110803220655.GE20966@hostway.ca> <20110803223949.GA20056@hostway.ca> <20110803231059.GB20056@hostway.ca> Content-Type: text/plain; charset=UTF-8 Cc: linux-btrfs , Josef Bacik To: Simon Kirby Return-path: In-reply-to: <20110803231059.GB20056@hostway.ca> List-ID: Excerpts from Simon Kirby's message of 2011-08-03 19:10:59 -0400: > On Wed, Aug 03, 2011 at 03:39:49PM -0700, Simon Kirby wrote: > > > On Wed, Aug 03, 2011 at 03:06:55PM -0700, Simon Kirby wrote: > > > > > I see Josef's 86d4a77ba3dc4ace238a0556541a41df2bd71d49 introduced the > > > bitmaps list. I could try temporarily reverting this (some fixups needed) > > > if anybody thinks my cache bouncing idea might be slightly possible. > > > > I'll try the attached and see how the profile changes. > > Hmm, I bound the SMP affinity of all of the btrfs processes to one CPU, > and the page dirtying rate got slower, so I suspect the writes aren't > really a big deal, and the problem is just that there is way too much > walking going on after rsync has ran for a while and loads everything > into memory. > > Any ideas? The current for-linus branch gets rid of all the bottlenecks in the metadata blocks. So now we're stuck with the bottlenecks in the allocator. There are a few simple things we can do here but Josef has a patch that fixes delalloc reservations for inline extents that might help as a first step. -chris