Messages in this thread | | | Subject | Re: [PATCH] sched: wakeup buddy | From | Mike Galbraith <> | Date | Fri, 08 Mar 2013 09:26:13 +0100 |
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On Fri, 2013-03-08 at 15:30 +0800, Michael Wang wrote: > On 03/08/2013 02:44 PM, Mike Galbraith wrote:
> > In general, I think things would work better if we'd just rate limit how > > frequently we can wakeup migrate each individual task. > > Isn't the wakeup buddy already limit the rate? and by turning the knob, > we could change the rate on our demand.
I was referring to the existing kernel, not as altered.
> We want > > jabbering tasks to share L3, but we don't really want to trash L2 at an > > awesome rate. > > I don't get it..., it's a task which has 'sleep' for some time, unless > there is no task running on prev_cpu when it's sleeping, otherwise > whatever the new cpu is, we will trash L2, isn't it?
I'm thinking if you wake it to it's old home after a microscopic sleep, it has a good chance of evicting the current resident, rescuing its L2. If tasks which do microscopic sleep can't move around at a high rate, they'll poke holes in fewer preempt victims. If they're _really_ fast switchers, always wake affine. They can't hurt much, they don't do much other than schedule off.
-Mike
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