[Libav-user] Best way to create a fractional ms timer?

"René J.V. Bertin" rjvbertin at gmail.com
Mon Apr 1 16:52:00 CEST 2013

On Apr 01, 2013, at 16:02, Nicolas George wrote:

> Le duodi 12 germinal, an CCXXI, "René J.V. Bertin" a écrit :
>> I may be mistaken, but I think that the higher your timer precision, the
>> lower the jitter such 'force-majeur' events produce (or, the jitter is
>> proportional to your timer's precision). Right?
> I believe you are wrong: you mix timer precision and time slice.
> On a NOHZ Linux x86_64 kernel and an idle system, the precision of nanosleep
> seems to be 100 µs, but if your system is busy, the process will be
> preempted for a full time slice, and that is much larger, above 500 µs.
> Regards,

In any case we seem to agree that it all depends on how the timer is implemented, and of course that goes both ways. Your nanosleep function that has a precision 100000x worse than what one might expect seems to be a good case in point.

(What's a NOHZ kernel?)

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