Mailing Lists: Apple Mailing Lists
 Image of Mac OS face in stamp
Re: real-time mode
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: real-time mode

on 11/29/01 2:57 PM, David Shaffer <email@hidden> wrote:

>> I still get popping every 20 seconds or so... ????
>> The input level seems to go to 0 for a few milliseconds.
>>
>
> I really feel that there is a thread priority problem with the IOProcs

Doubtful. The HAL's IOThreads are all time constraint threads. They tend to
run when they're supposed to run. On single processor systems, I generally
see 75-1505S of scheduling latency. On dual processor systems, it's usually
around 20-505S.

When they don't run as scheduled it is because the system is under severe
load (much more than just thrashing the mouse around will give you).

> If I, for instance, bring another application to the foreground and
> start moving the scrollbar back and forth, the app starts popping
> continuously.

Most likely your feeder threads just aren't running often enough. Elevating
their priority with the time constraint policy may be what you need.

If you aren't using a feeder thread, then you'll have to tell me a little
more about what you are doing so I can help figure out why you are getting
skipping.

> Also, attaching ThreadViewer causes continuous popping.

Attaching ThreadViewer requires doing lots of nasty things to the process in
the kernel. It isn't surprising that it causes glitches.

Attaching with gdb will doing the same thing, as do using printf and friends
in your IOProc.

> I was unable to find relevant docs on priority scheduling of threads;
> or, how to give the audio threads more priority.
>
> I am new to this discussion group (since 11/21/01) so I might not have
> access to some info that you have.

I'm pretty sure that this list is archived. My previous posts about the time
constraint policy and how to use it are probably the best documentation in
this context.

--

Jeff Moore
Core Audio
Apple

References: 
 >Re: real-time mode (From: David Shaffer <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2011 Apple Inc. All rights reserved.