On 2012-11-06 10:46, Dietmar Maurer wrote:
>>> This obviously breaks vhost when using multiple cores.
>>
>> With "obviously" you mean you already have a clue why?
>>
>> I'll try to reproduce.
> 
> No, sorry - just meant the performance regression is obvious (factor 20 to 40).
> 

OK. Did you try to bisect over qemu-kvm as well? I'm wondering if there
was a version of vhost there that didn't have this regression but was
also using direct IRQ delivery inside the kernel.

Jan