Top wakeups causers

[Adam Jackson]

On Sun, 2007-05-13 at 17:30 +0300, Aaron Baff wrote:

> And below all of those is Xorg, which seems to be split between
> do_setitimer (it_real_fn) and nv_start_rc_timer (nv_kern_rc_timer)
> functions.

This is going to come up a lot, so, let's get this one out of the way.

X uses setitimer() when it's actively servicing requests from clients.
It schedules an alarm for ~20ms in the future so that it can know when a
significant amount of time has elapsed, and therefore schedule other
clients if they're ready.  So at worst, it'd wake up 50 times a second,
but it'll only do so when it's already busy doing work.

Getting better accounting information out of X is definitely a goal, but
right now no one's working on it.  Until then you have to work backwards
from the other wakeup events to figure out what's waking up your X
server.

- ajax