[chuck-users] OSX updates =< real-time audio?

Stiefel, Van VStiefel at wcupa.edu
Mon Apr 14 10:13:40 EDT 2008


I think I have encountered this same problem using the same LiSa patch on two different machines. Hiccups occur on one at about 30% CPU and the other at 17-20% CPU. Both are MacBook Pros running 10 .4.11.

Maybe you can send me a simple test to run on both machines (since my poor hacking skills could always be an issue). 

What updates do you think cause the problems? My *good* running machine is the one least likely to have had any updates. 

I might be of service in identifying the problematic update(s) by examining the recent updates on both machines.

Van Stiefel
Assistant Professor
Department of Music Theory and Composition
Swope Music Building
College of Visual and Performing Arts
West Chester University
West Chester, PA 19383
Tel.: 610-436-2757

-----Original Message-----
From: chuck-users-bounces at lists.cs.princeton.edu on behalf of Ge Wang
Sent: Mon 4/14/2008 3:42 AM
To: ChucK Users Mailing List
Subject: Re: [chuck-users] OSX updates =< real-time audio?
Greetings again!

Following up... after additional testing on the inconsistent real-time 
behavior, we have found:

* buffer size has no apparent effect
* system scheduling priority (--level) has no apparent effect
* number of buffers has no apparent effect
* BLOCKING nearly fixes the problem, but this is undesirable because it 
is a bit more inefficient and also less amenable to really small buffer 
sizes, compared to CALLBACK.

To help make sure I am not going insane (faster than expected), I also 
tried running PD (both 40-2 and 41-4).  In both cases, similar audio 
hickups were occurring even when playing a single sine wave on my newly 
upgraded system.  At least on my setup, something is fairly wrong.  Not 
sure if it's the new software/firmware updates, or me doing something 
ill-advised (fairly standard M.O.), or something else altogether.

Any thoughts would be greatly appreciated!


On Sun, 13 Apr 2008, Ge Wang wrote:

> Greetings,
> We are experiencing some rather unfriendly real-time behavior on
> OS X, seemingly after doing the latest apple upgrades... here are
> some details, at least on my machine:
> * system: Macbook Pro / OS X (10.4.11)
> * updates: Quicktime 7.4.5 + MPB EFI Firmware Update 1.5
> * symptoms: real-time audio "goes to poop", even under moderate
>   loads.
> * workaround: running command line chuck in BLOCKING mode (via
> --blocking) seems to work, however the default CALLBACK mode seems
> completely hosed, even with bigger buffer sizes.  This is especially
> problematic for the miniAudicle, which doesn't have the option currently
> to choose between blocking vs. callback.
> Has anyone else noticed similar behavior, either on Tiger or Leopard?
> Or is this an isolated case for my system?  We'd appreciate any input!
> Thanks!!
> Best,
> Ge!
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