Re: [PATCH 3/4] sched: introduce synchronized idle injection

Jacob Pan
2015-11-18T14:11:09Z

On Wed, 18 Nov 2015 09:36:22 +0100
Ingo Molnar <mingo@kernel.org> wrote:

> >
> > This patch introduces a scheduler based idle injection method, it
> > works by blocking CFS runqueue synchronously and periodically. The
> > actions on all online CPUs are orchestrated by per CPU hrtimers.
> >
> > Two sysctl knobs are given to the userspace for selecting the
> > percentage of idle time as well as the forced idle duration for each
> > idle period injected.
>
> What's the purpose of these knobs? Just testing, or will some
> user-space daemon set them dynamically?
>
yes, it is to be used by userspace daemon such as thermal daemon.
Though there are interests from in kernel thermal governor but that is
another story.

> I also think that naming it 'idle injection' is pretty euphemistic:
> this is forced idling, right? So why not name it CFS_FORCED_IDLE?
yes, it is forced idle. sounds good.