Subject: Re: [linux-audio-dev] XAP spec & PTAF comments [merge]
From: David Olofson (david@olofson.net)
Date: Sun Feb 09 2003 - 00:55:00 EET
On Saturday 08 February 2003 13.17, Steve Harris wrote:
[...brachless clamp...]
> Its not an instruction its just a bit of maths using fabs().
Yes, of course! I keep forgetting that fabs() is an FPU operation. :-)
(Life's not that nice with ints on most CPUs...)
[...]
> > Besides, if you have seriously heavy plugins in combination with
> > this "a few effects at a time" behavior, the host could probably
> > optimize this a bit without plugins explicitly supporting it. It
> > means the host has to test buffers and figure out a clean way of
> > activating and deactivating plugins without side effects, but if
> > the plugins, or whole sub nets of plugins can be disabled, it's
> > still a big win. ...and doesn't require any API support
> > whatsoever, apart from the (de)activation stuff, which is needed
> > anyway.
>
> You still have unpredicatable CPU load, which makes it pretty
> useless.
If you want to make sure you *cannot* overload the CPU with the
current net, just have the host test it by turning all silent buffers
into cleared non-silent buffers.
Varying CPU load is not a problem in RT systems, but non-determinism
is. They may look confusingly similar from a practical POV, but
they're different things.
//David Olofson - Programmer, Composer, Open Source Advocate
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