Messages in this thread | | | Subject | Re: [RFC 0/3] Introduce per-task latency_tolerance for scheduler hints | From | Dietmar Eggemann <> | Date | Thu, 5 Dec 2019 10:24:33 +0100 |
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On 25/11/2019 10:46, Parth Shah wrote: > This patch series is based on the discussion started as the "Usecases for > the per-task latency-nice attribute"[1] > > This patch series introduces a new per-task attribute latency_tolerance to > provide the scheduler hints about the latency requirements of the task.
I forgot but is there a chance to have this as a per-taskgroup attribute as well?
> Latency_tolerance is a ranged attribute of a task with the value ranging > from [-20, 19] both inclusive which makes it align with the task nice > value. > > The value should provide scheduler hints about the relative latency > requirements of tasks, meaning the task with "latency_tolerance = -20" > should have lower latency than compared to those tasks with higher values. > Similarly a task with "latency_tolerance = 19" can have higher latency and > hence such tasks may bot care much about the latency numbers. > > The default value is set to 0. The usecases defined in [1] can use this > range of [-20, 19] for latency_tolerance for the specific purpose. This > patch does not define any use cases for such attribute so that any change > in naming or range does not affect much to the other (future) patches using > this. The actual use of latency_tolerance during task wakeup and > load-balancing is yet to be coded for each of those usecases.
This can definitely be useful for Android/EAS by replacing the current proprietary solution in android-google-common android-5.4:
commit 760b82c9b88d ("ANDROID: sched/fair: Bias EAS placement for latency") commit c28f9d3945f1 ("ANDROID: sched/core: Add a latency-sensitive flag to uclamp")
which links to usercase 6 (EAS) in [1].
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