Messages in this thread | | | Date | Thu, 6 Sep 2018 15:38:44 +0100 | From | Quentin Perret <> | Subject | Re: [PATCH v6 13/14] sched/topology: Make Energy Aware Scheduling depend on schedutil |
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Hi Rafael,
On Thursday 06 Sep 2018 at 11:18:55 (+0200), Rafael J. Wysocki wrote: > I'm not a particular fan of notifiers to be honest and you don't need > to add an extra chain just in order to be able to register a callback > from a single user.
Right. I agree there are alternatives to using notifiers. I used them because they're existing infrastructure, and because they let me do what I want without too much troubles, which are two important points.
> That can be achieved with a single callback > pointer too, but also you could just call a function exported by the > scheduler directly from where in the cpufreq code it needs to be > called.
Are you thinking about something comparable to what is done in cpufreq_add_update_util_hook() (kernel/sched/cpufreq.c) for example ? That would probably have the same drawback as my current implementation, that is that the scheduler is notified of _all_ governor changes, not only changes to/from sugov although this is the only thing we care about for EAS.
We could also hook things in sugov_start & sugov_stop directly, and keep all changes into the scheduler ... That is slightly harder to implement on the scheduler topology side, though.
Thoughts ?
> > Also, is there any hope that the 12 first patches could make it in 4.20 > > on their own ? Or is it already too late ? > > I'm walking through them right now, albeit somewhat slowly due to > various distractions, so we'll see.
Thanks ! Quentin
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