From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Ehrhardt Subject: Re: [kvm-ppc-devel] virtio-net working on PowerPC KVM Date: Mon, 31 Mar 2008 06:52:04 +0200 Message-ID: <47F06DF4.3090200@linux.vnet.ibm.com> References: <1206743597.5432.50.camel@basalt> <47EF6BE8.80202@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Cc: kvm-ppc-devel , kvm-devel , Hollis Blanchard To: Avi Kivity Return-path: In-Reply-To: <47EF6BE8.80202@qumranet.com> 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 Avi Kivity wrote: > Hollis Blanchard wrote: >> I'm pleased to report that we now have working network support in the >> guest, via the virtio-net driver. In fact, we can use NFS for the >> guest's root filesystem. :) Boot log attached. >> >> = > = > Congrats! > = >> The bad news is that it's very slow, but the good news is that it's nice >> to be improving performance rather than debugging mysterious >> crashes... ;) >> >> With this milestone reached, in the near future I intend to start >> sending patches to Avi and linuxppc-dev for review, hopefully for >> inclusion in 2.6.26. However, I do want to see if we can improve the >> performance a little bit first... >> = > = > Low virtio net performance may be due to the virtio net host timer. = > What's your guest/host ping latency? I would be happy about 0.25ms atm :-). The current ping latency to the Host= or other PC's is around 7-8ms (native sys is ~0.15ms). We are investigating performance improvements in general and also some chan= ges in the setup e.g. booting from virtio-block as alternative for some spe= edup. > Even if you have a good hrtimer implementation, I think you'll see = > 0.25ms latency, and that may be enough to slow down nfs. Unfortunately = > virtio is tuned for throughput at this time (it should be easy to = > disable the timer when we detect the queue is usually empty). > = -- = Gr=FCsse / regards, = Christian Ehrhardt IBM Linux Technology Center, Open Virtualization ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace