From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joe Thornber Subject: Re: New dm-bufio with shrinker API Date: Tue, 6 Sep 2011 09:50:38 +0100 Message-ID: <20110906085038.GA3619@ubuntu> References: <20110905090428.GA3826@ubuntu> <20110905144913.GB22386@ubuntu> <20110905150714.GA2722@infradead.org> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20110905150714.GA2722@infradead.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development Cc: Christoph Hellwig , Mikulas Patocka List-Id: dm-devel.ids On Mon, Sep 05, 2011 at 11:07:15AM -0400, Christoph Hellwig wrote: > On Mon, Sep 05, 2011 at 03:49:14PM +0100, Joe Thornber wrote: > > I changed the test suite to reset the peak_allocated parameter before > > each test and record it at the end of each test. It's very hard to > > say what is right and wrong when talking about cache sizes, since you > > always have to qualify anything by saying 'for this particular load'. > > However, I think bufio could be more aggressive about recycling cache > > entries. With the old block manager the test suite ran nicely with > > less than 256k, from memory I think I started seeing slow down around > > 128k. With bufio I'm seeing consistently larger cache sizes for the > > same performance. > > IS there any reason you'll need a fixed size? This is fairly similar in > concept to the XFS buffercache, which does perfectly well by allocation > memory as needed, and letting the shrinker reclaim buffers when under > memory pressure. This is exactly what we're trying to do. - Joe