On Wed, 16 Nov 2016 11:40:14 +0100
Peter Zijlstra [off-list ref] wrote:

On top of which, the implementation had issues; now I know you're the
blinder kind of person that disregards everything not in his immediate
interest, but if you'd looked at the patch you'd have seen he'd added
code the idle entry path, which will slow down every single to-idle
transition.

Isn't to-idle a bit bloated anyway? Or has that been fixed. I know
there was some issues with idle_balance() which can add latency to
wakeups. idle_balance() is also in the to-idle path.

Note, that this is a sched feature which would be a nop (jump_label)
when disabled. And I'm sure it could also be optimized to be a static
inline as well when it is enabled.

I'm not saying we need to go this approach, but I'm just saying that
the to-idle issue is a bit of a red herring.

-- Steve