Am 13.11.2012 um 17:26 schrieb Michael S. Tsirkin: > On Tue, Nov 13, 2012 at 05:21:50PM +0100, Peter Lieven wrote: >> On 13.11.2012 17:22, 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. >> which ubuntu version in the guest? >> >> Peter > > ubuntu-10.04.4-server-amd64.iso
can you try with vnet_hdr=on on the nic. the bug seems to be only relevant when vhost-net is used. Dietmar, see you implications with normal virtio? Peter
