On Jul 24, 2006, at 4:13 AM, Dirk Stegemann wrote:
This works perfectly fine; as soon as the app launches, the values
returned by 'getTimeInMilliseconds()' are very low (starting at
zero), increasing during runtime of the app.
But on an Intel-Mac, the time stamps are increased differently than
on a PPC Mac:
On Intel hardware, the time is increased constantly, independently
from the programs current cpu usage.
On PPC hardware, the time is increased only when the cpu is used.
That is, when calling 'sleep()' or 'usleep()' on PPC hardware, the
timer which is queried by 'mach_absolute_time()' appearently is
stopped, whereas it continues to run on a Intel hardware.
Is this behavior documented somewhere? I've been counting on this to
increment monotonically at a constant rate and not be affected by
sleep or any other sort of behavior such as running multiple threads
at once (on different processors) not affecting this.
Is there an explanation what is causing this difference in behaviour?
And if so, is there a way to get a monotonic clock with microsecond
precision that isn't affected by anything like this?
--
Steve Checkoway
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