[PATCH v2 7/7] ARM: smp: Add runtime PM support for CPU hotplug

[Thomas Gleixner]

On Tue, 22 Sep 2015, Lina Iyer wrote:
> Talking to John Stultz at Linaro Connect: Is cpuidle relevant in
> -RT kernel? I dont know much about -RT. I thought this might be point
> that we should consider.

There are definitely RT systems out there where power consumption is a
concern.
 
> As it stands today, on a 800 Mhz ARM quad core, I am seeing a latency of
> 50-70 usec for the additional runtime PM in the cpuidle. Ofcourse, there
> is a definite need to optimize and there are opportunities to do that.

RT is not about being fast. RT is about being deterministic. So if a
power sensitive RT system can afford the extra latencies induced by PM
it will tolerate them. Of course, optimizing that is not a bad thing
at all :)
 
Thanks,

	tglx