Messages in this thread | | | Date | Tue, 7 May 2019 16:04:25 +0100 | From | Quentin Perret <> | Subject | Re: [RFC PATCH 2/6] sched/dl: Capacity-aware migrations |
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On Tuesday 07 May 2019 at 16:17:33 (+0200), luca abeni wrote: > Hi Quentin, > > On Tue, 7 May 2019 14:35:28 +0100 > Quentin Perret <quentin.perret@arm.com> wrote: > > > Hi Luca, > > > > On Monday 06 May 2019 at 06:48:32 (+0200), Luca Abeni wrote: > > > +static inline int dl_task_fit(const struct sched_dl_entity *dl_se, > > > + int cpu, u64 *c) > > > +{ > > > + u64 cap = (arch_scale_cpu_capacity(NULL, cpu) * > > > arch_scale_freq_capacity(cpu)) >> SCHED_CAPACITY_SHIFT; > > > > I'm a little bit confused by this use of arch_scale_freq_capacity() > > here. IIUC this means you would say a big DL task doesn't fit on a big > > CPU just because it happens to be running at a low frequency when this > > function is called. Is this what we want ? > > The idea of this approach was to avoid frequency switches when > possible; so, I wanted to check if the task fits on a CPU core at its > current operating frequency. > > > > If the frequency is low, we can (probably) raise it to accommodate > > this DL task so perhaps we should say it fits ? > > In a later patch, if the task does not fit on any core (at its current > frequency), the task is moved to the core having the maximum capacity > (without considering the operating frequency --- at least, this was my > intention when I wrote the patches :)
Ah, I see, patches 05-06. I'll go have a look then !
Thanks, Quentin
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