Messages in this thread | | | Subject | Re: [Patch v8 4/7] sched/fair: Enable periodic update of average thermal pressure | From | Dietmar Eggemann <> | Date | Mon, 27 Jan 2020 13:09:12 +0100 |
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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:
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>> 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() [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 functions are doing the same thing, scaling capacity by something (cpu, frequency or thermal)?
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