Re: time constraint policy and audio proc calls
Re: time constraint policy and audio proc calls
- Subject: Re: time constraint policy and audio proc calls
- From: Kurt Revis <email@hidden>
- Date: Wed, 12 Dec 2001 04:49:59 -0800
Following up to this very useful post from a few weeks ago, with some
more details:
On Monday, November 19, 2001, at 12:26 PM, Jeff Moore wrote:
computation: the amount of time until the thread can be pre-empted
Feeder thread's should be pre-emptible after a very very small
amount of
time, if not immediately. So, set this number very small, if not to
0.
I tried to set a thread's scheduling policy to time-constraint, using a
0 value for computation as you suggested. However, the thread_policy_set
call always returned an error (KERN_INVALID_ARGUMENT).
Fortunately, it was really easy to find this function in the Darwin
kernel source. It turns out that values for computation must be strictly
between min_rt_quantum and max_rt_quantum. Currently those two values
are hard-coded to be 50 microseconds and 50 milliseconds, as far as I
can tell. So I set my computation to 50 us, and it worked fine.
Hope this helps someone save some time. (It is really cool to be able
to look at the kernel source... this part, at least, was not nearly as
daunting as I expected it to be.)
--
Kurt Revis
email@hidden