Re: Luvalley-2 has been released: running KVM below any operating system

[Avi Kivity <avi@redhat.com>]

Xiaodong Yi wrote:
> Hi,
>
> I've tested the guest Linux using UnixBench 5.1.2. The platform is:
>   * Intel's Core Due CPU with 2 cores, 2GB RAM
>   * CentOS 5.2 as the dom0 Linux, i.e., the host Linux for KVM
>   * CentOS 5.2 as the guest Linux, i.e., the Linux running on the
> virtual machine provided by Qemu
>
> The first set of results is for Luvalley, and the second one is for
> KVM. As the result, Luvalley's guest Linux is 20% ~ 30% faster than
> KVM's guest! It is very surprise to me. I had through Luvalley's guest
> should be the same performance as KVM's.
>
>   

Yes, it is surprising.

> Double-Precision Whetstone                    12287.7 MWIPS (10.0 s, 2 samples)
> Double-Precision Whetstone                     2166.3 MWIPS (10.2 s, 2 samples

That's by far the biggest difference. Can you confirm it isn't a typo?

If not, then it looks like we have a bug in floating point handling. I
don't think this benchmark uses sse.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.