Messages in this thread | | | Date | Mon, 20 Feb 2012 20:39:48 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: sched: Performance of Trade workload running inside VM |
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* Peter Zijlstra <a.p.zijlstra@chello.nl> [2012-02-20 15:56:30]:
> > Another variant of the patch could be to have select_idle_sibling() look > > for any idle cpu that is in same cache domain (rather than looking for a > > whole group of cpus to be idle)? > > Right, so I looked over select_idle_sibling() again and it made my head > hurt :/
I can vouch for it :-)
> I can't immediately tell if its actually doing the right thing > or not (it _should_ try and avoid using SMT siblings if possible).
Yes makes sense.
> It would be very nice not to have both select_idle_sibling() and > SD_BALANCE_WAKE iterate the domain tree. So merging them if at all > possible would be goodness I think.
Right. Let me see how that can be worked out in my next version.
> We'd have WAKE_AFFINE to decide which cache domain etc to stuff the task > on and then use select_idle_sibling() to find the most appropriate cpu > within that cache domain. > > There was talk of modifying select_idle_sibling() to also consider the > C-state the cpu was in, preferring shallower over deeper C-states where > there's choice,
Ok ..interesting. /me goes and educates himself how this info can be dug out.
> this is very similar to what you propose, taking the > least loaded cpu when there isn't a proper idle one around.
Thanks for the feedback ..
- vatsa
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