From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shirley Ma Subject: Re: Network performance with small packets Date: Tue, 01 Feb 2011 14:59:57 -0800 Message-ID: <1296601197.26937.833.camel@localhost.localdomain> References: <20110127.130240.104065182.davem@davemloft.net> <1296163838.1640.53.camel@localhost.localdomain> <20110128121616.GA8374@redhat.com> <1296523838.30191.39.camel@sridhar.beaverton.ibm.com> <1296594585.26937.817.camel@localhost.localdomain> <20110201212411.GD30770@redhat.com> <1296595955.26937.822.camel@localhost.localdomain> <20110201214211.GB31105@redhat.com> <1296597185.26937.829.camel@localhost.localdomain> <20110201215603.GA31348@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Sridhar Samudrala , Steve Dobbelstein , David Miller , kvm@vger.kernel.org, mashirle@linux.vnet.ibm.com, netdev@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from e3.ny.us.ibm.com ([32.97.182.143]:40496 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751052Ab1BAXAF (ORCPT ); Tue, 1 Feb 2011 18:00:05 -0500 In-Reply-To: <20110201215603.GA31348@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, 2011-02-01 at 23:56 +0200, Michael S. Tsirkin wrote: > There are flags for bytes, buffers and packets. > Try playing with any one of them :) > Just be sure to use v2. > > > >I would like to change it to > > half of the ring size instead for signaling. Is that OK? > > > > Shirley > > > > > > Sure that is why I made it a parameter so you can experiment. The initial test results shows that the CPUs utilization has been reduced some, and BW has increased some with the default parameters, like 1K message size BW goes from 2.5Gb/s about 2.8Gb/s, CPU utilization down from 4x% to 38%, (Similar results from the patch I submitted a while ago to reduce signaling on vhost) but far away from dropping packet results. I am going to change the code to use 1/2 ring size to wake the netif queue. Shirley