Re: [RFC PATCH 00/17] virtual-bus

[Avi Kivity]

Herbert Xu wrote:
> On Thu, Apr 02, 2009 at 07:54:21PM +0300, Avi Kivity wrote:
>   
> > 3ms latency for ping?
> >
> > (ping will always be scheduled immediately when the reply arrives if I  
> > understand cfs, so guest load won't delay it)
> >     
>
> That only happens if the guest immediately does some CPU-intensive
> computation 3ms and assuming its timeslice lasts that long.
>   

Note that this happens even if the computation is SCHED_BATCH.

> In any case, the same thing will happen right now if the host or
> some other guest on the same CPU hogs the CPU for 3ms.
>
>   

If the host is overloaded, that's fair.  But millisecond latencies 
without host contention is not a good result.

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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