[Tinyos-host-mote-wg] Re: [Tinyos-2.0wg] TinyOS Telecon Notes 8/31/05

[Joe Polastre]

> > Besides, 60-80 cycles is at most 20us of computation.  Considering it
> > takes longer than that for the Atmel to wake up, I don't see a problem
> > doing the computation.
> This code runs every time the system handles an interrupt. Think of
> it as adding an overhead in that regard. Given that it is in an
> atomic section, this means that it is part of the critical path that
> defines the maximum interrupt handling rate. This is the most
> fundamental OS primitive (the task scheduler): we should make it as
> efficient as possible without making it too complex. Doesn't the
> msp430 wake up in something like 6us?

I've measured that the scheduler idle loop in TinyOS 1.x takes 30us,
so the extra 20us to check the power state isn't that bad.  If you can
get down that idle loop, then I'll buy the argument that the 20us is
critical ;)

Phil, basically you're proposing that we keep the HPLPowerManagementM
with adjustPower() where adjustPower() sets a dirty bit that is
checked when the node goes to sleep.

-Joe


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