Messages in this thread | | | Date | Tue, 6 Mar 2018 19:56:14 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 1/4] sched/fair: add util_est on top of PELT |
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On Thu, Feb 22, 2018 at 05:01:50PM +0000, Patrick Bellasi wrote: > +/** > + * Estimation Utilization for FAIR tasks. > + * > + * Support data structure to track an Exponential Weighted Moving Average > + * (EWMA) of a FAIR task's utilization. New samples are added to the moving > + * average each time a task completes an activation. Sample's weight is > + * chosen so that the EWMA will be relatively insensitive to transient changes > + * to the task's workload. > + * > + * @enqueued: instantaneous estimated utilization of a task/cpu > + * task: the task's util_avg at last task dequeue time > + * cfs_rq: the sum of util_est.enqueued for each RUNNABLE task on that CPU > + * > + * Thus, the util_est.enqueued of a task represents the contribution on the > + * estimated utilization of the CPU where that task is currently enqueued. > + * > + * @ewma: the Exponential Weighted Moving Average (EWMA) utilization of a task > + * Only for tasks we track a moving average of the past instantaneous > + * estimated utilization. This allows to absorb sporadic drops in > + * utilization of an otherwise almost periodic task. > + * > + */
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