[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] RE: [Xen-devel] vif interface dropping 80% packets
> I'm trying to characterize the performance of 10G ethernet to a user > domain. > The machine has 2 configured ethernet cards, eth0 is a 1G card, and eth2 is > a 10G card. (eth1 is another 1G card and eth3 is another 10G, but these > are not configured) > I have network bridge set up on eth2 with defaults, nothing special, just: > /etc/xen/scripts/network-bridge start vifnum=2 > I have a user domain that attaches eth1 to this vif, and when I try netperf > tests, I get tons of packet loss in the vif interface. > > As can be seen above, vif3.1 drops about 80% of the packets it should > transmit. Is this expected due to something in the dom0 -> domU interface > just not being able to keep up, or is there something I can do about it? > It almost looks like the dom0->domU link is throttled at about 1Gb/s. I > say this because the 10G link is running about 50-60% capacity when the > drop rate is 80%. First off, try switching to 3.0.4 and use the included 2.6.16-xen kernel. How are you measuring the bandwidth? It's much more realistic to use TCP as open-loop UDP blasts aren't used by any real protocols. > Everything has MTU 1500, btw - I noticed that Xen is pretty unhappy with an > MTU of 9000. In what way? I'd expect larger MTUs to work OK, though I haven't tested them myself. Does the larger MTU work in dom0, but not through to other domU's? You may need to set the MTU on the bridge and all vif's. Ian _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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