Messages in this thread |  | | Date | Tue, 22 Mar 2022 06:40:46 -1000 | From | Tejun Heo <> | Subject | Re: [RFC 6/6] sched/fair: Add sched group latency support |
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Hello,
On Tue, Mar 22, 2022 at 05:10:36PM +0100, Vincent Guittot wrote: > latency_nice is quite similar to nice. The nice latency is used as an > index to get a latency weight in the range [-1024:1024]. latency_nice > is in the range [-20:19] and latency_prio shifts it in the range > [0:40] . This index is then used to get the latency weight similar to > how the nice prio is used to get a weight. That being said, the > latency should probably reflect the latency_weight instead of the > latency_prio in order to be aligned with the weight and weight.nice > fields of cgroups. > > As described in patch 5 commit message, the weight is then used to > compute a relative offset to check whether the waking task can preempt > the current running task.
So, what I'm trying to say is if it is actually a weight, just use weight values instead of arbitrary mapped nice values. Nobody can tell how the latency nice value of -2 compares against, say, 3. If you can define it clearly in terms of weights (or something else clearly describable), it'd be a lot better.
Thanks.
-- tejun
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