Re: Process wakeups when idle and power consumption

Peter Geoghegan <peter(at)2ndquadrant(dot)com> writes:
> Attached is the first in what I hope will become a series of patches
> for reducing power consumption when idle.

Cool. This has been on my personal to-do list for awhile, but it keeps
on failing to get to the top, so I'm glad to see somebody else putting
time into it.

The major problem I'm aware of for getting rid of periodic wakeups is
the need for child processes to notice when the postmaster has died
unexpectedly. Your patch appears to degrade the archiver's response
time for that really significantly, like from O(1 sec) to O(1 min),
which I don't think is acceptable. We've occasionally kicked around
ideas for mechanisms that would solve this problem, but nothing's gotten
done. It doesn't seem to be an easy problem to solve portably...

> + * The caveat about signals invalidating the timeout of
> + * WaitLatch() on some platforms can be safely disregarded,

Really?

regards, tom lane