Can anyone provide any pointers as to what might cause virtio networking to be slow (~55Mb/s)? Here's what I've tried so far:
Guests tried: Windows Server 2003 x32 SP2 UP guest w/ Windows guest drivers ver 3 Windows Server 2003 x64 SP2 SMP guest w/ Windows guest drivers ver 3 On the host: On all the hosts I'm using CentOS 5.2 x64. Two of the three physical servers I've tried are dual Intel Xeon E5430s (Dell 2950s). The third server is a Dual Opteron 2350 (Dell R805). All the servers are brand new and have almost no load currently. I've tried using KVM-79 built against the stock 2.6.18 kernel, KVM-79 built against a custom 2.6.27.8 kernel, and git (on 12/10/08) built against 2.6.27.8. In all cases, I've made sure to copy the if_tun.h and virtio*.h from my current kernel includes into the kernel/include/linux directory in my kvm-79 or kvm-userspace source tree before building, since I've heard this is necessary to enable GSO support, although I've also been told that lacking GSO shouldn't make it quite as slow as it is. In all cases, when I test throughput from the guest using virtio to the host's br0 (the bridge the guest is joined to), I get somewhere between 55Mb/s and 150Mb/s. This is even less than I get with the rtl8139 and e1000 emulation (between 200 and 350 Mb/s). Everything else with this host and guest works great. Pings from guest to host are perfect (on the intel servers, not on the amd server but that's another issue I believe). Is there something I could be doing wrong during my host kernel config, or during my kvm build, etc that could cause virtio to work, but so slowly? Any ideas are greatly appreciated. -Adrian -- 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
