select/poll/usleep precision on FreeBSD vs Linux vs OSX

[Bakul Shah]

On Thu, 01 Mar 2012 11:33:46 +1100 Bruce Evans <brde at optusnet.com.au>  wrote:
> Linux and OSX must be using busy-waiting or expensive timer
> reprogramming for short timeouts to work.

Linux-2.6.17 or later have two options: CONFIG_NO_HZ for on
demand timer interrupts (to reduce power use on idle systems)
and CONFIG_HIGH_RES_TIMERS for as accurate timers as h/w would
allow. And yes, timers are reprogrammed (as per a June 23,
2006  kerneltrap.org article).