[gmpi] Re: Topic 3: Cross platform
- From: David Olofson <david@xxxxxxxxxxx>
- To: gmpi@xxxxxxxxxxxxx
- Date: Thu, 6 Mar 2003 00:34:51 +0100
On Wednesday 05 March 2003 20.04, Angus F. Hewlett wrote:
[...]
> > Scenario 2: Suppose somebody writes a plugin that fiendishly
> > allocates memory during streaming, off a multithreaded heap.
> > Users wonder why multiple instances of this plugin perform so
> > badly in a heavily multithreaded host. We could expose a host
> > allocator that prohibits allocations during live streaming.
>
> But then unless you MANDATE the host memory-allocation callback,
> the developer will just go away and do it the "bad" way anyway :(
This is where "support for soft real time operations in hard real time
systems" come in. Basically, we have to provide ways for plugins to
do "risky" stuff without blocking the host real time thread.
The alternative is to simply mark plugins that need to do these things
as incompatible with real time processing, and IMNSHO, that's
completely useless.
<technical>
One idea considered for XAP is "worker callbacks"; a very simple
threading API meant for (re)allocating buffers, doing massive
calculations, off-line rendering, loading from disk and other stuff
that either takes too much time, or is nondeterministic. It's not
"real" threading, as there are only two sync points for a worker
callback: the host call to start it (host calls a function in another
thread) and the event that tells the plugin that the worker callback
has returned.
</technical>
//David Olofson - Programmer, Composer, Open Source Advocate
.- The Return of Audiality! --------------------------------.
| Free/Open Source Audio Engine for use in Games or Studio. |
| RT and off-line synth. Scripting. Sample accurate timing. |
`-----------------------------------> http://audiality.org -'
--- http://olofson.net --- http://www.reologica.se ---
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