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Re: [Xen-devel] Scheduling of I/O domains
> On Fri, 2004-08-06 at 03:25, G. Milos wrote:
> > The patch you sent probably does work, but most of the code responsible
> > for waking up got pushed into specific schedulers (i.e. it is not in
> > schedule.c but in sched_bvt.c, sched_rrobin.c etc). I have replaced the
> > "min <= now" bit by what BVT research paper suggests and only
> > 0.7% difference was observed in the dd test. It would be nice if you could
> > run the dd test on your machine after updating your xen code.
> I ran my dd test with the latest xen bits, checked out today. The result
> dd test all by itself: best run 1.93s
> dd test with another domain running an infinite loop: best run 2.5s
> Well this is certainly much better than the 8s it was taking before, but
> it's still giving up more than 25% in performance.
Is this running on the same processor? If so, I think its pretty
reasonable that we loose 25% of IO performance when only getting
50% of the CPU.
The downside of giving the driver domain absolute priority over
guest domains would be that we might end up doing more context
switches than necessary, and loose the benefit of batching.
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