On Mar 31, 2008, at 6:52 AM, Christian Ehrhardt wrote: > 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 changes in the setup e.g. booting from virtio-block as > alternative for some speedup.
I am experiencing 7-8ms ping latencies (native 0.1ms) on x86_64 as well, when pinging the virtual machine. Maybe it's not related to PowerPC? Is it supposed to be that slow? > > >> 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). >> Alex ------------------------------------------------------------------------- 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 _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
