Re: [coreaudio] Re: Latest Documentation?
Re: [coreaudio] Re: Latest Documentation?
- Subject: Re: [coreaudio] Re: Latest Documentation?
- From: marquis logan <email@hidden>
- Date: Fri, 15 Feb 2002 17:42:08 -0500
On Friday, February 15, 2002, at 02:43 AM, robert wrote:
I wonder if using real-time extensions is really necessary to be able
to do
what CoreAudio does.
core audio creates rt threads on your behalf. the call back thread is
rt. core audio also wires a 4k buffer or so iirc.
if you follow the darwin lists, the rt threads in x will probably become
"contagious" as the migrate around in future releases.
One document which I have read about this, and which might concur with
this, is:
http://mambo.peabody.jhu.edu/~karlmac/publications/latency-icmc2001.pdf
(also mentioned on the url you mention above). This document shows that
stock OSX (an 'old' version even, judging from the document) has lower
latency _under heavy loads_ than a patched Linux.
I figure this is because the CoreAudio developers have, afaik, focussed
primarily on achieving low latency by optimising kernel/userspace
transitions and using AltiVec for what its good in, instead of
resorting to
RT patches or even rt-queues (which I think wouldn't be hard to port
from
FreeBSD, and which might already result to even lower latency).
Btw, mlock() is available in Darwin :)
robert
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