On Thu, 2008-07-24 at 15:56 -0500, Anthony Liguori wrote: > Hi Mark, > > Mark McLoughlin wrote: > > Hey, > > Here's a bunch of patches attempting to improve the performance > > of virtio_net. This is more an RFC rather than a patch submission > > since, as can be seen below, not all patches actually improve the > > perfomance measurably. > > > > I'm still seeing the same problem I saw with my patch series. Namely, > dhclient fails to get a DHCP address. Rusty noticed that RX has a lot > more packets received then it should so we're suspicious that we're > getting packet corruption.
I've just tried bridging to my physical LAN and DHCP seems to be working fine. Which reminds me, though - doing this makes host->guest throughput drop to well below pre-GSO figures. GSO appears to be disabled while there's a physical interface on the bridge. If I remove eth0, the figures jump right back up again. I also just noticed that the GSO patch breaks e1000 because it unconditionally sets IFF_VNET_HDR. Will fix that up. > Configuring the tap device with a static address, here's what I get with > iperf: > > w/o patches: > > guest->host: 625 Mbits/sec > host->guest: 825 Mbits/sec > > w/patches > > guest->host: 2.02 Gbits/sec > host->guest: 1.89 Gbits/sec > > guest lo: 4.35 Gbits/sec > host lo: 4.36 Gbits/sec I tried iperf at one point and was getting really low figures; not sure why. Apart from your iperf figures being lower than my netperf figures, it also contradicts what I was seeing - namely guest->host beating host->guest before the patches and host->guest beating guest->host after the patches. It could all just be down to the length of the tx timer. If you try adjusting that does it help? > This is with KVM GUEST configured FWIW. Yep, same here. Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
