Re: [Qemu-devel] [question] virtio-blk performance degradationhappened with virito-serial

[Paolo Bonzini]

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