Messages in this thread | | | Date | Wed, 25 Mar 2015 19:14:13 +0100 | From | Peter Zijlstra <> | Subject | Re: [RFCv3 PATCH 33/48] sched: Energy-aware wake-up task placement |
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On Wed, Mar 25, 2015 at 06:01:22PM +0000, Juri Lelli wrote:
> Yes and no, IMHO. It makes perfect sense to trigger cpufreq on the > target_cpu's freq domain, as we know that we are going to add p's > utilization there.
Fair point; I mainly wanted to start this discussion so that seems to have been a success :-)
> Anyway, I was thinking that we could just > rely on triggering points in {en,de}queue_task_fair and task_tick_fair. > We end up calling one of them every time we wake-up a task, perform > a load balancing decision or just while running the task itself > (we have to react to tasks phase changes). This way we should be > able to reduce the number of triggering points and be more general > at the same time.
The one worry I have with that is that it might need to re-compute which P state to request, where in the above (now trimmed quoted) code we already figured out which P state we needed to be in, any hook in enqueue would have forgotten that.
> > So does it make sense to at least put in the right hooks now? I realize > > we'll likely take cpufreq out back and feed it to the bears but > > something managing P states will be there whatever we'll call the new > > fangled thing and this would be the place to hook it still. > > > > We should be able to clean up and post something along this line > fairly soon.
Grand!
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