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

Ge Wang ge at ccrma.Stanford.EDU
Mon Apr 14 03:42:59 EDT 2008

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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