On 01/09/14 16:03, Christian Borntraeger wrote: > On 01/09/14 15:29, Paolo Bonzini wrote: >> Il 01/09/2014 15:22, Christian Borntraeger ha scritto: >>>>> If virtio-blk and virtio-serial share an IRQ, the guest operating system has to check each virtqueue for activity. Maybe there is some inefficiency doing that. >>>>> AFAIK virtio-serial registers 64 virtqueues (on 31 ports + console) even if everything is unused. >>>> >>>> That could be the case if MSI is disabled. >>> >>> Do the windows virtio drivers enable MSIs, in their inf file? >> >> It depends on the version of the drivers, but it is a reasonable guess >> at what differs between Linux and Windows. Haoyu, can you give us the >> output of lspci from a Linux guest? >> >> Paolo > > Zhang Haoyu, which virtio drivers did you use? > > I just checked the Fedora virtio driver. The INF file does not contain the MSI enablement as described in > http://msdn.microsoft.com/en-us/library/windows/hardware/ff544246%28v=vs.85%29.aspx > That would explain the performance issues - given that the link information is still true. Sorry, looked at the wrong inf file. The fedora driver does use MSI for serial and block. -- 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
