Re: TODO list for qemu+KVM networking performance v2

On Wed, Jun 10, 2009 at 07:08:49PM +0300, Avi Kivity wrote:

Michael S. Tsirkin wrote:

quoted

On Wed, Jun 10, 2009 at 06:18:01PM +0300, Avi Kivity wrote:
  

quoted

Michael S. Tsirkin wrote:
    

quoted

But I don't understand how aio will make implementing it easier -
or are you merely saying that it will make it worthwhile?
        

If you have aio, the the NIC and the guest proceed in parallel.  If 
the  guest is faster (likely), then when it sends the next packet it 
will see  that interrupts are disabled and not notify again.  Once 
aio complete we  can recheck the queue; if it's empty we reenable 
notifications.  If  there's still stuff in it we submit it with 
notifications disabled.
    

So you are saying that with aio we won't need this optimization at all?
I guess it's late in the day, and my mind is fuzzy...
  

No, I'm saying with aio the optimization becomes worthwhile.  But I  
joined late in the thread so we may be talking about different things.

Oh, I see that. What Rusty's saying is that it's not as
trivial as it seems, and I agree. And at some point it
seemed like he was saying it's easier to implement with
aio, but that probably was just my misunderstanding.

-- 
MST