On Wed, Nov 1, 2017 at 12:35 PM, Steve Muckle <smuc...@google.com> wrote: > On 10/30/2017 12:02 PM, Joel Fernandes wrote: >>> >>> Also, this more looks like a policy decision. Will it be better to >>> put that directly into schedutil? Like this: >>> >>> if (cpu_idle()) >>> "Don't change the freq"; >>> >>> Will something like that work? >> >> >> I thought about this and I think it wont work very well. In the >> dequeue path we're still running the task being dequeued so the CPU is >> not yet idle. What is needed here IMO is a notion that the CPU is >> possibly about to idle and we can get predict that from the dequeue >> path of the CFS class. >> >> Also just looking at whether the CPU is currently idle or not in the >> governor doesn't help to differentiate between say the dequeue path / >> tick path. Both of which can occur when the CPU is not idle. >> >> Any thoughts about this? > > > Also if it really is the case that this bit of policy is universally > desirable, I'd think it is better to do this in the scheduler and avoid a > needless trip through a fn pointer out to schedutil for performance reasons.
I agree. Peter, what do you think? Are you Ok with the approach of this patch (preventing of the cpufreq update call during dequeue)? thanks, - Joel
