Re: timers in AudioHardwarePlugin
Re: timers in AudioHardwarePlugin
- Subject: Re: timers in AudioHardwarePlugin
- From: Stefan Werner <email@hidden>
- Date: Mon, 4 Aug 2003 18:40:03 +0200
Hi Philippe,
On Sunday, Aug 3, 2003, at 16:04 Europe/Berlin, Philippe Wicker wrote:
For instance, a call to a 10 microsec sleep time using nanosleep
takes an average time of about 25 microsec on a DP867. Using usleep
yields similar results. The error may however be greater than (25
minus 10) because this is a best case value (everything is on the L1
cache, the 1st call to nanosleep takes about 65 microsec) and the cpu
may be used by some other threads while your's is sleeping and be
yielded the cpu again a much longer time after (depending on its
scheduling and priority settings).
Thanks, that'll work for now. Since I'm using that as a replacement for
the audio hardware's buffer interrupt, usleep() is OK, I'm using sleep
times in the magnitude of msecs - a jitter of <50 microsecs should be
fine for my applications. Also, I think that being a plugin of the HAL
should give my thread a higher priority than most tasks. I just wasn't
sure wether it's appropriate to use POSIX calls for timing inside the
HAL or if the CoreAudio is providing its own function for timing.
Stefan
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