FROMLIST: sched/cpufreq: Prepare schedutil for Energy Aware Scheduling
Schedutil requests frequency by aggregating utilization signals from the scheduler (CFS, RT, DL, IRQ) and applying a 25% margin on top of them. Since Energy Aware Scheduling (EAS) needs to be able to predict the frequency requests, it needs to forecast the decisions made by the governor. In order to prepare the introduction of EAS, introduce schedutil_freq_util() to centralize the aforementioned signal aggregation and make it available to both schedutil and EAS. Since frequency selection and energy estimation still need to deal with RT and DL signals slightly differently, schedutil_freq_util() is called with a different 'type' parameter in those two contexts, and returns an aggregated utilization signal accordingly. While at it, introduce the map_util_freq() function which is designed to make schedutil's 25% margin usable easily for both sugov and EAS. As EAS will be able to predict schedutil's frequency requests more accurately than any other governor by design, it'd be sensible to make sure EAS cannot be used without schedutil. This will be done later, once EAS has actually been introduced. Change-Id: Idbeeb00926045507b73f9cba37630b38ae0816c0 Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Suggested-by:Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Quentin Perret <quentin.perret@arm.com> Message-Id: <20181016101513.26919-3-quentin.perret@arm.com> Signed-off-by:
Quentin Perret <quentin.perret@arm.com>
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