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 15:03:51 +0100 |
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On 05/12/2019 11:49, Valentin Schneider wrote: > > On 05/12/2019 09:24, Dietmar Eggemann wrote: >> 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? >> > > Peter argued we should go for task attributes first, and then > cgroup/taskgroups later on: > > https://lore.kernel.org/lkml/20190905083127.GA2332@hirez.programming.kicks-ass.net/
OK, I went through this thread again. So Google or we have to provide the missing per-taskgroup API via cpu controller's attributes (like for uclamp) for the EAS usecase.
After reading:
https://lore.kernel.org/r/20190905114030.GL2349@hirez.programming.kicks-ass.net
IMHO the following mapping of the existing Android (binary) latency_sensitive per-taskgroup flag makes sense:
latency_sensitive=1 -> latency_tolerance*[-20 .. -1] (less tolerant, more sensitive)
latency_sensitive=0 -> latency_tolerance[0 .. 19] (more tolerant, less sensitive)
Default value is 0 so not latency_sensitive.
* Since we use [-20 .. 19] as values for latency_tolerance we could name it latency_nice. It's shorter ... ?
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