First Attempt - 'usleep()' or 'nanosleep()'

• These functions will sleep a given ammount of time (usleep is BSDish and accepts micro-seconds, nanosleep is POSIX and accepts 'struct timespec', which contains nano-seconds).
• nanosleep also tells us how much time is left to sleep, in case we were woken prematurely (e.g. by receiving a signal). More on the use of this later.
• They both suffer from the Linux-timeslice effect - they will sleep at least the minimal time-resolution of the kernel (1/1024 on i386 hardware with a 2.6 kernel, 1/100 with a 2.4 kernel, etc).
• Thus, to sleep less - we need to avoid sleeping at all, and use busy-wait.

Originally written by guy keren