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Re: MP audio output
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Re: MP audio output


  • Subject: Re: MP audio output
  • From: Jeff Moore <email@hidden>
  • Date: Wed, 27 Mar 2002 14:49:25 -0800

on 3/21/02 8:04 PM, Kurt Bigler <email@hidden> wrote:

> So before I give up, forgive me but I just have to ask: by any chance,
> would it be fairly easy for apple to just remove the restriction of one
> callback thread per device per application in order to provide a simple
> architecture for multi-cpu-capable audio-intensive applications like mine?

Not only would this be a fairly difficult task (means re-writing a great
deal of the IO thread code in the HAL), but it is highly wasteful of system
resources since it would involve more time constraint threads than you
really need. In fact, this could have exactly the opposite effect on your
performance as the load in the IO threads increases and the time left for
the rest of the system, like UI handling and file IO, decreases.

I cannot stress enough how important it is to minimize the number of time
constraint threads you use to solve a problem. More often than not (and
definitely in your case), you will get much better performance by using
normal threads at a reasonable priority (especially once the Window Server
issues are ironed out). And again, the audio system doesn't really have
anything to help you out here.

So to sum up, I doubt very much that having multiple IO threads will
accomplish what you are trying to do.

--

Jeff Moore
Core Audio
Apple
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References: 
 >Re: MP audio output (From: Kurt Bigler <email@hidden>)

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