From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/2] Batch writes to MMIO Date: Wed, 23 Apr 2008 20:13:14 +0300 Message-ID: <480F6E2A.2030809@qumranet.com> References: <12089560583282-git-send-email-Laurent.Vivier@bull.net> <480F4237.90202@qumranet.com> <1208960577.4281.17.camel@frecb07144> <480F4A4E.7010008@qumranet.com> <480F516E.3030407@codemonkey.ws> <480F51F4.5000202@qumranet.com> <480F5A0C.1040503@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Laurent Vivier To: Anthony Liguori Return-path: In-Reply-To: <480F5A0C.1040503@codemonkey.ws> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Anthony Liguori wrote: > Avi Kivity wrote: > >> Anthony Liguori wrote: >> >>> The ne2k is pretty mmio heavy. You should be able to observe a boost >>> with something like iperf (guest=>host) I would think if this is a >>> real savings. >>> >>> >> If we're just improving ne2k, the complexity isn't worth it. We have >> two better nics which are widely supported in guests. >> > > Sure, but the ne2k should be pretty close to an optimal synthetic > benchmark for batching. If we don't see a big improvement with it, > we're probably not going to see a big improvement with it for anything. > I disagree. If there are other inefficiencies in ne2k, they will mask any performance improvement from batching. So whatever result we get will be inconclusive. I don't expect any massive performance improvement except for splash screens. I'll be happy to settle for a few percent with e1000 or scsi or ide. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone