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SubjectRe: [RFC] maximum latency tracking infrastructure
Date
On Thursday, August 24, 2006 10:41 am, Arjan van de Ven wrote:
> The reason for adding this infrastructure is that power management in
> the idle loop needs to make a tradeoff between latency and power
> savings (deeper power save modes have a longer latency to running code
> again).

What if a processor was already in a sleep state when a call to
set_acceptable_latency() latency occurs? Should there be a callback so
they can be woken up? A callback would also allow ACPI to tell the
user "disabling C3 because of device <foo>" or somesuch, which might be
nice.

Also, should subsystems have the ability to set a lower bound on
latency? That would mean set_acceptable_latency() could fail,
indicating that the user should buy a better device or a system with
better realtime guarantees, which is also valuable info.

Comments aside, this is a nice interface, should help clarify things for
devices with response time limits.

Thanks,
Jesse
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