Messages in this thread |  | | From | Vincent Guittot <> | Date | Tue, 15 Mar 2022 18:07:37 +0100 | Subject | Re: [RFC 6/6] sched/fair: Add sched group latency support |
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On Tue, 15 Mar 2022 at 01:59, Josh Don <joshdon@google.com> wrote: > > On Fri, Mar 11, 2022 at 8:15 AM Vincent Guittot > <vincent.guittot@linaro.org> wrote: > > > [snip] > > > > static struct cftype cpu_legacy_files[] = { > > @@ -10649,6 +10673,11 @@ static struct cftype cpu_legacy_files[] = { > > .read_s64 = cpu_idle_read_s64, > > .write_s64 = cpu_idle_write_s64, > > }, > > + { > > + .name = "latency", > > + .read_s64 = cpu_latency_read_s64, > > + .write_s64 = cpu_latency_write_s64, > > + }, > > #endif > > #ifdef CONFIG_CFS_BANDWIDTH > > { > > @@ -10866,6 +10895,18 @@ static struct cftype cpu_files[] = { > > .read_s64 = cpu_idle_read_s64, > > .write_s64 = cpu_idle_write_s64, > > }, > > + { > > + .name = "latency", > > + .flags = CFTYPE_NOT_ON_ROOT, > > + .read_s64 = cpu_latency_read_s64, > > + .write_s64 = cpu_latency_write_s64, > > + }, > > + { > > + .name = "latency.nice", > > + .flags = CFTYPE_NOT_ON_ROOT, > > + .read_s64 = cpu_latency_nice_read_s64, > > + .write_s64 = cpu_latency_nice_write_s64, > > + }, > > Something I considered when adding cpu.idle was that negative values > could be used to indicate increasing latency sensitivity. Folding the > above latency property into cpu.idle could help consolidate the > "latency" behavior, especially given that it shouldn't really be > possible to configure an entity as both latency sensitive and idle.
The range of latency nice is [-19:20] and it doesn't touch on the weight whereas sched_idle behavior impacts both the shares and the preemption so I was afraid of possible confusion with what latency nice is doing
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