Chris Friesen <chris.friesen@xxxxxxxxxxx> wrote on 06/27/2011 09:15:05 AM: > > On Fri, 2011-06-24 at 15:10 -0600, Chris Friesen wrote: > >> Is anyone working on SR-IOV for KVM, specifically for networking? Or is > >> virtio good enough that it's not a pressing concern? In IBM's recent postings of results for the SPECvirt benchmark on RHEL 6.0 [1] we used SR-IOV for the network adapter for most of the guests. The adapters in the host were the Intel x520 10 Gigabit Server adapters (lscpi says Intel Corporation 82599EB 10-Gigabit SFI/SFP+ Network Connection (rev 22) ). virtio may be good enough for lighter workloads, but there was no way we could get the higher guest counts for SPECvirt with the performance of virtio. We needed the performance of SR-IOV. > For SR-IOV I assume I need to configure the PF in the host, enable some > number of VFs, pass through a VF to each guest and load the vf driver. > Is that right? That is correct. You also need to make sure your guest has the driver for the virtual function. As an example, on my qemu command line I have the options: -pcidevice host=8b:10.0\ -net none\ I use the "-net none" option because the qemu I am running likes to do you a favor and create a network device for you if you didn't specify one (it doesn't know that the PCI device is a network device). Without "-net none", what can happen is that qemu will create an emulated network device for you (e.g., e1000), and the guest will most likely have a driver for it that it will load. If you don't have the driver in the guest for the virtual function, you can still get network connectivity to the guest and may think you are using SR-IOV when you are not. > Do I need to configure a software bridge to allow the guests to talk to > each other? You do not need to configure a software bridge. The adapter on the host behaves like a switch and routes traffic between the virtual functions. (I don't know offhand if the traffic between the virtual functions is looped back by the adapter or if it actually goes out the adapter port and comes back in.) Steve D. [1] http://www.spec.org/virt_sc2010/results/specvirt_sc2010_perf.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
