Dietmar Maurer wrote: >> Dietmar, how is the speed if you specify --machine pc,kernel_irqchip=off >> as >> cmdline option to qemu-kvm-1.2.0? > > I get full speed if i use that flag. > >
I also tried to reproduce it and can confirm your findings. Host Ubuntu 12.04 LTS (kernel 3.2) with vanilla qemu-kvm 1.2.0, vhost-net and an Ubuntu 10.4.4 (Linux 2.6.32) as guest. Vhost-Net performance drops by approx. factor 50-100 if I do not disable kernel_irqchip. Normal Virtio and e1000 seems to work fine.
