Messages in this thread | | | From | Vincent Guittot <> | Date | Mon, 27 Jan 2020 16:15:04 +0100 | Subject | Re: [Patch v8 4/7] sched/fair: Enable periodic update of average thermal pressure |
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On Mon, 27 Jan 2020 at 13:09, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: > > On 24/01/2020 16:45, Vincent Guittot wrote: > > On Fri, 24 Jan 2020 at 16:37, Dietmar Eggemann <dietmar.eggemann@arm.com> wrote: > >> > >> On 17/01/2020 16:39, Vincent Guittot wrote: > >>> On Fri, 17 Jan 2020 at 15:55, Peter Zijlstra <peterz@infradead.org> wrote: > >>>> > >>>> On Fri, Jan 17, 2020 at 02:22:51PM +0100, Vincent Guittot wrote: > >>>>> On Thu, 16 Jan 2020 at 16:15, Peter Zijlstra <peterz@infradead.org> wrote: > > [...] > > >> The 'now' argument is one thing but why not: > >> > >> -int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity) > >> +int update_thermal_load_avg(u64 now, struct rq *rq) > >> { > >> + u64 capacity = arch_cpu_thermal_pressure(cpu_of(rq)); > >> + > >> if (___update_load_sum(now, &rq->avg_thermal, > >> > >> This would make the call-sites __update_blocked_others() and > >> task_tick(_fair)() cleaner. > > > > I prefer to keep the capacity as argument. This is more aligned with > > others that provides the value of the signal to apply > > > >> > >> I guess the argument is not to pollute pelt.c. But it already contains > > > > you've got it. I don't want to pollute the pelt.c file with things not > > related to pelt but thermal as an example. > > > >> arch_scale_[freq|cpu]_capacity() for irq. > > But isn't arch_cpu_thermal_pressure() not exactly the same as > arch_scale_cpu_capacity() and arch_scale_freq_capacity()? > > All of them are defined by default within the scheduler code > [include/linux/sched/topology.h or kernel/sched/sched.h] and can be > overwritten by arch code with a fast implementation (e.g. returning a > per-cpu variable). > > So why is using arch_scale_freq_capacity() and arch_scale_cpu_capacity() > in update_irq_load_avg [kernel/sched/pelt.c] and update_rq_clock_pelt()
As explained previously, update_irq_load_avg is an exception and not the example to follow. update_rt/dl_rq_load_avg are the example to follow and fixing update_irq_load_avg exception is on my todo list
> [kernel/sched/pelt.h] OK but arch_cpu_thermal_pressure() in > update_thermal_load_avg() [kernel/sched/pelt.c] not? > > Shouldn't arch_cpu_thermal_pressure() not be called > arch_scale_thermal_capacity() to highlight the fact that those three
Quoted from cover letter https://lkml.org/lkml/2020/1/14/1164: " v6->v7: - ... - Renamed arch_scale_thermal_capacity to arch_cpu_thermal_pressure as per review comments from Peter, Dietmar and Ionela. -...
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> functions are doing the same thing, scaling capacity by something (cpu, > frequency or thermal)?
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