An overload, in the context of Core Audio, basically means that the
HAL's IO thread failed to meet it's real time deadline. The usual
cause for this sort of problem is that the IOProc took too long to
finish executing. I can't speak to your circumstances without seeing
more evidence (e.g. a Shark trace, the IO cycle telemetry, etc), but
when I see this happen in apps, it is caused by either them just
trying to do too much work in the allocated time or they are doing
something silly like blocking on a mutex or something like that.
Note, that the number of CPUs really has no bearing on this phenomenon
since there is only one IO thread and it is the amount of time this
thread spends running doing the signal processing or whatever that
The usual course for a developer to take when they see overloads that
seem to be caused by using their plug-in is to start profiling with
Shark, see where the time is being spent, and optimize accordingly.
You might want to use AULab to test with to give you a little more
control over the environment.
On Mar 4, 2008, at 7:40 AM, Daniel Stenning wrote:
I am naturally trying to use Logic8 as my "reference" sequencer when
on my AudioUnit plugin project but time and time again when
play logic songs that incorporate my plugin, I end up getting the
Take a look here just to see the amount of traffic and heat this
Is it not time this was fixed ? OSX is meant to be the "musicians"
OS and Logic8 is made by the same company.
Very often this message crops up when using MIDI AU instruments so
must be something going on here.
We now have 8 core CPUS and a supposedly multicore friendly leopard
Logic8 still seems to be having problems with songs that are hardly
in terms of complexity. What is going on ?.
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