Re: [PATCH] vhost: Add polling mode

Michael S. Tsirkin
2014-07-29T10:44:26Z

On Tue, Jul 29, 2014 at 01:30:03PM +0300, Razya Ladelsky wrote:

[..] had to snip off the quoted text, it's mangled up to
unreadability.
Please take a look at Documentation/email-clients.txt
to fix this.

> > This is an optimization patch, isn't it?
> > Could you please include some numbers showing its
> > effect?
> >
> >
>
> Hi Michael,
> Sure. I included them in a reply to Jason Wang in this thread,
> Here it is:
> http://www.spinics.net/linux/lists/kvm/msg106049.html
>

Hmm there aren't a lot of numbers there :(. Speed increased by 33% but
by how much? E.g. maybe you are getting from 1Mbyte/sec to 1.3,
if so it's hard to get excited about it. Some questions that come to
mind: what was the message size? I would expect several measurements
with different values. How did host CPU utilization change?

What about latency? As we are competing with guest for host CPU,
would worst-case or average latency suffer?

Thanks,

--
MST