Re: sched: Performance of Trade workload running inside VM

[Peter Zijlstra]

On Wed, 2012-02-15 at 23:08 +0530, Srivatsa Vaddagiri wrote:
> * Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> [2012-02-15 18:24:11]:
> 
> > On Wed, 2012-02-15 at 22:40 +0530, Srivatsa Vaddagiri wrote:
> > > Ok ..let me see if these numbers highlight the problem better.
> > 
> > does this translate like: I've no fscking clue,
> 
> I'd mentioned a possible reason earlier which is limiting VM1 to reach higher
> utilization (which is the time it waits for cpu after wakeup):
> 
> >b. In the "all VMs active" case, VM1's vcpu tasks were found to incur
> >   "high" wait times when ttwo of VM1's tasks were scheduled on the same
> >   CPU (i.e a VCPU task had to wait behind a sibling VCPU task for
> >   obtaining CPU resource).
> 
> Let me get cpu wait time data and post it by tomorrow.
> 
> > but my tinker made it go away?
> 
> Do you have any other suggestions for me to try?

I'm still waiting for a problem description that isn't a book.

What does the load-balancer do, why is it wrong, why does your patch
sort it etc.

I've really no idea what you're trying to do, other than make your
numbers improve (which while a noble goal, doesn't help in judging your
patch or suggesting alternative means of getting there).
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