Messages in this thread | | | Date | Tue, 7 May 2019 15:31:27 +0100 | From | Quentin Perret <> | Subject | Re: [RFC PATCH 1/6] sched/dl: Improve deadline admission control for asymmetric CPU capacities |
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On Tuesday 07 May 2019 at 16:25:23 (+0200), luca abeni wrote: > On Tue, 7 May 2019 14:48:52 +0100 > Quentin Perret <quentin.perret@arm.com> wrote: > > > Hi Luca, > > > > On Monday 06 May 2019 at 06:48:31 (+0200), Luca Abeni wrote: > > > diff --git a/drivers/base/arch_topology.c > > > b/drivers/base/arch_topology.c index edfcf8d982e4..646d6d349d53 > > > 100644 --- a/drivers/base/arch_topology.c > > > +++ b/drivers/base/arch_topology.c > > > @@ -36,6 +36,7 @@ DEFINE_PER_CPU(unsigned long, cpu_scale) = > > > SCHED_CAPACITY_SCALE; > > > void topology_set_cpu_scale(unsigned int cpu, unsigned long > > > capacity) { > > > + topology_update_cpu_capacity(cpu, per_cpu(cpu_scale, cpu), > > > capacity); > > > > Why is that one needed ? Don't you end up re-building the sched > > domains after this anyways ? > > If I remember correctly, this function was called at boot time when the > capacities are assigned to the CPU cores. > > I do not remember if the sched domain was re-built after this call, but > I admit I do not know this part of the kernel very well...
Right and things moved recently in this area, see bb1fbdd3c3fd ("sched/topology, drivers/base/arch_topology: Rebuild the sched_domain hierarchy when capacities change")
> This achieved the effect of correctly setting up the "rd_capacity" > field, but I do not know if there is a better/simpler way to achieve > the same result :)
OK, that's really an implementation detail, so no need to worry too much about it at the RFC stage I suppose :-)
Thanks, Quentin
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