0 (disabled) or 1 (enabled)
No. Causes new system timing variable to be set at boot time. Not referenced after boot.
When you want timeouts with a resolution of less than 10 milliseconds and greater than or equal to 1 millisecond.
0 to MAXINT
No. Increasing value can cause a system crash.
When default number of timers offered by system is inadequate. Applications see an EAGAIN error when executing timer_create system calls.