Rusty Russell wrote:
>
> On Wed, 24 Jul 2002 11:48:10 -0700 (PDT)
> Linus Torvalds <torvalds@transmeta.com> wrote:
>
> > The thing is, we cannot change existing select semantics, and the
> > question is whether what most soft-realtime wants is actually select, or
> > whether people really want a "waittimeofday()".
>
> NOT waittimeofday. You need a *new* measure which can't be set forwards
> or back if you want this to be sane. pthreads has absolute timeouts (eg.
> pthread_cond_timedwait), but they suck IRL for this reason.
>
> Of course, doesn't need any correlation with absolute time, it could be a
> "microseconds since boot" kind of thing.
>
The POSIX clocks & timers API defines CLOCK_MONOTONIC for
this sort of thing (CLOCK_MONOTONIC can not be set). It
also defines an API for clock_nanosleep() that CAN use an
absolute time which is supposed to follow any clock setting
that is done. Combine the two and you have a fixed time
definition.
AND, guess what, the high-res-timers patch does all this and
more.
-- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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