Messages in this thread | | | Date | Tue, 8 May 2018 13:52:42 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH] Revert "cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily" |
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On 08-05-18, 08:33, Dietmar Eggemann wrote: > This reverts commit e2cabe48c20efb174ce0c01190f8b9c5f3ea1d13. > > Lifting the restriction that the sugov kthread is bound to the > policy->related_cpus for a system with a slow switching cpufreq driver, > which is able to perform DVFS from any cpu (e.g. cpufreq-dt), is not > only not beneficial it also harms Enery-Aware Scheduling (EAS) on > systems with asymmetric cpu capacities (e.g. Arm big.LITTLE). > > The sugov kthread which does the update for the little cpus could > potentially run on a big cpu. It could prevent that the big cluster goes > into deeper idle states although all the tasks are running on the little > cluster.
I think the original patch did the right thing, but that doesn't suit everybody as you explained.
I wouldn't really revert the patch but fix my platform's cpufreq driver to set dvfs_possible_from_any_cpu = false, so that other platforms can still benefit from the original commit.
-- viresh
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