Re: [Ksummit-discuss] [TECH(CORE?) TOPIC] Energy conservation bias interfaces

["Iyer, Sundar" <sundar.iyer@intel.com>]

> -----Original Message-----
> From: Preeti U Murthy [mailto:preeti@linux.vnet.ibm.com]
> Sent: Thursday, May 8, 2014 2:30 PM
> To: Iyer, Sundar; Peter Zijlstra; Rafael J. Wysocki
> Cc: Brown, Len; Daniel Lezcano; Ingo Molnar; ksummit-

> True that 'race to halt' also ends up saving energy. But when the kernel goes
> conservative on energy, the scheduler would look at racing to idle *within a
> power domain* as much as possible. Only if the load crosses a certain
> threshold would it spread across to other power domains.

I think Rafael mentioned in an another thread about shared supplies and resources.
In such a case, the race-to-idle within a power domain may actually negate the overall
platform savings.

And to confirm, you are referring to generic power domains beyond the CPU right?

> These are general heuristics. These simple heuristics must work out for most
> platforms but may not work for all. If it works for majority of the cases then
> I believe we can safely call it a success.

And which is why I mentioned that this is heavily platform dependent. This is 
completely dependent on how the rest of the system power management works.

Cheers!