On Tue, Nov 13, 2012 at 06:22:56PM +0200, Michael S. Tsirkin wrote:
On Tue, Nov 13, 2012 at 12:49:03PM +0100, Peter Lieven wrote:
On 09.11.2012 19:03, Peter Lieven wrote:
Remark:
If i disable interrupts on CPU1-3 for virtio the performance is ok again.
Now we need someone with deeper knowledge of the in-kernel irqchip and the
virtio/vhost driver development to say if this is a regression in qemu-kvm
or a problem with the old virtio drivers if they receive the interrupt on
different CPUs.
anyone?
Looks like the problem is not in the guest: I tried ubuntu guest
on a rhel host, I got 8GB/s with vhost and 4GB/s without
on a host to guest banchmark.
Tried with upstream qemu on rhel kernel and that's even a bit faster.
So it's ubuntu kernel. vanilla 2.6.32 didn't have vhost at all
so maybe their vhost backport is broken insome way.