On Thursday 20 September 2007, David Baron wrote:
> Question is: How does ticklessness effect audio? Realtime-preemptive
> kernels? Other multimedia?

Not negative, more likely positive as the timer is programmed
with the specific timeout until the next event. In periodic mode
there is a slack factor of half the period, that is the scheduler
could be called half the timer period too late. A one-shot timer
will be programmed to trigger at the exact point in time when
the event is planned.

You can compare this with wakeing up yourself every Minute on
the morning to look if you have to get at 7am. When you are
look at 6:59:30 the last time then you will note that it is
time to get up at 7:00:30, that are 30 seconds too late. But
you could program a one-shot timer at 6:59:30 for 30 seconds
which would trigger at exactly 7:00:00.

You could increase the precision with periodic timers by decreasing
the interval, say you check every 10 seconds, then you are at most
9 seconds too late. But this is more effort. It is better to
program a one-shot timer at 0:00am for 7 hours to get woken up
at exactly 7:00am. And if a new event has to be inserted before
the one-shot timer triggers, then the timer has just to be
reprogrammed.

Note, that for my understanding, the Linux kernel normally works
in periodic mode and switches to one-shot mode when the system
is idle for an amount of time.

Kind regards,

Frank
-- 
Dr.-Ing. Frank Mehnert    innotek GmbH, http://www.innotek.de

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