Messages in this thread | | | Date | Wed, 17 Feb 2021 17:10:27 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH V3 1/2] topology: Allow multiple entities to provide sched_freq_tick() callback |
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On 17-02-21, 11:30, Ionela Voinescu wrote: > The problem is not topology_scale_freq_invariant() but whether a scale > factor is set for some CPUs. > > Scenario (test system above): > - "AMUs" are only supported for [1-2], > - cpufreq_supports_freq_invariance() -> false > > What should happen: > - topology_scale_freq_invariant() -> false (passed) > - all CPUs should have their freq_scale unmodified (1024) - (failed) > because only 2 out of 6 CPUs have a method of setting a scale factor > > What does happen: > - arch_set_freq_tick() -> topology_set_freq_tick() will set a scale > factor for [1-2] based on AMUs. This should not happen. We will end > up with invariant signals for bigs and signals that are not freq > invariant for littles.
Another case. cpufreq is included as a module and AMU is implemented partially.
- first time cpufreq driver is inserted, we set up everything and freq_scale gets updated on ticks.
- remove cpufreq driver, we are back in same situation.
We can't control it that way.. Or we add another call layer in middle before the tick-handler gets called for AMU, which will check if we are fully invariant or not ?
-- viresh
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