From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Sending packet at fixed rate really bad performance Date: Mon, 28 Sep 2009 10:17:31 -0400 Message-ID: <20090928141731.GA7107@phenom.dumpdata.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Marco Tizzoni Cc: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Sun, Sep 27, 2009 at 07:26:49PM +0200, Marco Tizzoni wrote: > Hi all, > I'm doing some tests about i/o performance and cpu overhead in dom0. > I've coded a small tool that can sends UDP packets at fixed rate or > flood. While sending packet at fixed rate I'm experiencing performance > problem, related to how Xen =A0handle signal, I guess. >=20 > On my laptop (Core2 duo P8700), with no Xen running, I can send > packets at a rate of 20k, 40k, 60k, 80k/s achieving an actual packet > rate per second pretty near to the requested rate. >=20 > On Xen (dom0 with no guest running and no load - Athlon 64 dual core > 4000+ ), the performance are really bad. Lets narrow this down a bit. You are comparing two different systems with potentially different interfaces. Lets concentrate on one machine first. Is the performance on your Athlon 64 without Xen (meaning you boot without Xen) in the same ball-park figure? I want to make sure we can eliminate the hardware being at fault here.