Messages in this thread | | | Date | Fri, 22 Dec 2017 12:07:37 +0000 | From | Patrick Bellasi <> | Subject | Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates |
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On 22-Dec 12:46, Peter Zijlstra wrote: > On Fri, Dec 22, 2017 at 11:02:06AM +0000, Patrick Bellasi wrote: > > > @@ -315,8 +315,8 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time) > > > unsigned long j_util, j_max; > > > s64 delta_ns; > > > > > > - if (j_sg_cpu != sg_cpu) > > > - sugov_get_util(j_sg_cpu); > > > + if (idle_cpu(j)) > > > + continue; > > > > That should work to skip IDLE CPUs... however I'm missing where now we > > get the sugov_get_util(j_sg_cpu) for active CPUs. It has been moved > > somewhere else I guess... > > No, I'm just an idiot... lemme fix that.
Then you just missed a call to sugov_get_util(j_sg_cpu) after the above if... right, actually that was Viresh proposal...
> > Moreover, that way don't we completely disregard CFS blocked load for > > IDLE CPUs... as well as DL reserved utilization, which should be > > released only at the 0-lag time? > > I was thinking that since dl is a 'global' scheduler the reservation > would be too and thus the freq just needs a single CPU to be observed;
AFAIU global is only the admission control (which is something worth a thread by itself...) while the dl_se->dl_bw are aggregated into the dl_rq->running_bw, which ultimately represents the DL bandwidth required for just a CPU.
> but I suppose there's nothing stopping anybody from splitting a clock > domain down the middle scheduling wise. So yes, good point.
That makes sense... moreover, using the global utilization, we would end up asking for capacities which cannot be provided by a single CPU.
> Blergh that'd make a mess of things again.
Actually, looking better at your patch: are we not just ok with that?
I mean, we don't need this check on idle_cpu since in sugov_aggregate_util we already skip the util=sg_cpu->max in case of !rq->rt.rt_nr_running, while we aggregate just CFS and DL requests.
-- #include <best/regards.h>
Patrick Bellasi
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