Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement

From: Morten Rasmussen
Date: Tue Mar 24 2015 - 13:46:54 EST


On Tue, Mar 24, 2015 at 03:53:52PM +0000, Peter Zijlstra wrote:
> On Tue, Mar 24, 2015 at 03:42:42PM +0000, Morten Rasmussen wrote:
> > Right, I agree that we should preferably do the normal thing for U ~= 1.
> > We can restructure the wake-up path to follow that pattern, but we need
> > to know U beforehand to choose the right path. U isn't just
> > get_cpu_usage(prev_cpu) but some broader view of the of the cpu
> > utilizations. For example, prev_cpu might be full, but everyone else is
> > idle so we still want to try to do an energy aware wake-up on some other
> > cpu. U could be the minium utilization of all cpus in prev_cpu's
> > sd_llc, which is somewhat similar to what energy_aware_wake_cpu() does.
>
> Yeah, or a setting in the root domain set by the regular periodic load
> balancer; that already grew some mojo to determine this in a patch I
> recently commented on.

Yes, I was thinking something like that too.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/