Re: [PATCH v2] schedutil: Allow cpufreq requests to be made even when kthread kicked

[Viresh Kumar]

On 21-05-18, 10:20, Joel Fernandes wrote:
> On Mon, May 21, 2018 at 06:00:50PM +0100, Patrick Bellasi wrote:
> > If that's the case, this means that if, for example, during a
> > frequency switch you get a request to reduce the frequency (e.g.
> > deadline task passing the 0-lag time) and right after a request to
> > increase the frequency (e.g. the current FAIR task tick)... you will
> > enqueue a freq drop followed by a freq increase and actually do two
> > frequency hops?

I don't think so.

Consider the kthread as running currently and has just cleared the
work_in_progress flag. Sched update comes at that time and we decide
to reduce the frequency, we queue another work and update next_freq.
Now if another sched update comes before the kthread finishes its
previous loop, we will simply update next_freq and return. So when the
next time kthread runs, it will pick the most recent update.

Where is the problem both of you see ?

-- 
viresh