usleep

KAYVEN RIESE kayve at sfsu.edu
Fri Feb 22 22:28:51 UTC 2008


On Fri, 22 Feb 2008, Heiko Wundram (Beenic) wrote:

> Am Freitag, 22. Februar 2008 11:28:42 schrieb Sharad Chandra:
>> 	Does usleep work for you? i just saw it is implemented over nanosleep
>> which passes a struct timeval to "select".
>
> Quoting from POSIX:
>
> """
> The usleep() function will cause the calling thread to be suspended from
> execution until either the number of real-time microseconds specified by the
> argument useconds has elapsed or a signal is delivered to the calling thread
> and its action is to invoke a signal-catching function or to terminate the
> process. The suspension time may be longer than requested due to the
> scheduling of other activity by the system.
> """

oh.. you DID say "microseconds"  .. i was going to assume complete 
ignorance in pointing out that "u" is used because it looks remotely
like the greek letter "mu" which is the metric abbreviation for "micro"
wich is 10^-6

hope i am not being real obvious.

>
> See the last sentence, specifically.
>
> So, yes, the behaviour you're seeing is pretty much expected, simply because
> _user_ processes are scheduled in timeslices, which depend on the HZ setting
> of the kernel.
>
> -- 
> Heiko Wundram
> Product & Application Development
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