Messages in this thread | | | Date | Thu, 24 Feb 2011 15:40:20 -0500 (EST) | From | Nicolas Pitre <> | Subject | Re: [PATCH V5 2/2] tracing, perf : add cpu hotplug trace events |
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On Thu, 24 Feb 2011, Peter Zijlstra wrote:
> On Thu, 2011-02-24 at 15:24 -0500, Nicolas Pitre wrote: > > > Most SMP ARM processors are going to use it soon. Powering down idle > > cores provides substantial power saving. > > And why can't regular idle paths be used? CPU hotplug is a massively > expensive operation.
The idle path assumes that the CPU state is preserved. We're talking about cores completely going down with power pulled beneath them and eventually rebooted dynamically here.
Nicolas
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