[linux-audio-dev] XAP spec & PTAF comments [merge]

[David Olofson]

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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