Re: Limit to registered IO procs ?
Re: Limit to registered IO procs ?
- Subject: Re: Limit to registered IO procs ?
- From: Andy <email@hidden>
- Date: Fri, 21 Feb 2003 23:38:52 +0000
Begin forwarded message:
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From: Andy <email@hidden>
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Date: Fri Feb 21, 2003 23:37:44 Europe/London
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To: Jeff Moore <email@hidden>
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Subject: Re: Limit to registered IO procs ?
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On Friday, Feb 21, 2003, at 19:45 Europe/London, Jeff Moore wrote:
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> The only limits are memory.
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> But, why do you want to add so many IOProcs at once? This is
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> expensive as the HAL has to allocate resources for things that aren't
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> going to be in use.
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> It is much more efficient to register a single IOProc and to dispatch
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> to your specialized IOProcs from there.
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Thanks for the info.
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I would question "more efficient" ? In terms of speed surely not ?
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Admittedly the gain is small, but it is a gain, and I'm trying to
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squeeze the last ounces out our slow (ish) machines .. ;-) (pushing
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as many as 20+ channels of audio around , I need as many cycles as I
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can get).
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I'll change the method so that only the proc that is currently
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required is actually registered at any one time, The decision isn't
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required at runtime, I think that would be better than dispatching to
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external functions. After all why go to the bother of optimising only
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to add the overhead of an unnecessary function dispatcher. I hope
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AudioDeviceReleaseIOProc does actually release those expensive
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resources ?
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Perhaps at some time the documentation could mention that IOProc
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registration is expensive. I did presume it existed to do just the job
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that I was using it for. That is: one could create a set of IOProcs
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that could be dispatched from AudioDeviceStart /before/ the
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expensive decision needs to be done in the IOProc.
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Are there any other issues regarding resource allocation in the HAL ?
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It would be interesting to know where are the high risk areas and what
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the affects are.
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