From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [RFC v1 0/5] VBD: enlarge max segment per request in blkfront Date: Thu, 13 Sep 2012 09:21:55 -0400 Message-ID: <20120913132153.GC16635@localhost.localdomain> References: <20120907174922.GA13040@phenom.dumpdata.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Duan, Ronghui" Cc: "Stefano.Stabellini@eu.citrix.com" , "Ian.Jackson@eu.citrix.com" , "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On Thu, Sep 13, 2012 at 02:28:12AM +0000, Duan, Ronghui wrote: > > form xentop. > > > Read 1K random IOPS Dom0 CPU DomU CPU% > > > W 52005.9 86.6 71 > > > W/O 52123.1 85.8 66.9 > > > > So I am getting some different numbers. I tried a simple 4K read: > > > > [/dev/xvda1] > > bssplit=4K > > rw=read > > direct=1 > > size=4g > > ioengine=libaio > > iodepth=64 > > > > And with your patch got: > > read : io=4096.0MB, bw=92606KB/s, iops=23151 , runt= 45292msec > > > > without: > > read : io=4096.0MB, bw=145187KB/s, iops=36296 , runt= 28889msec > > > What type of backend file you are using? In order to remove the influence of cache in Dom0, I use a physical partition as backend. > In code level, although there is some overhead in my patch compared to original, but it should not to be so big. :) Right :-) phy:/dev/sda,xvda,w The sda is a Corsair SSD.