[LAD] "enhanced event port" LV2 extension proposal

David Olofson david at olofson.net
Wed Nov 28 15:52:21 UTC 2007

On Wednesday 28 November 2007, Krzysztof Foltman wrote:
> I don't think it's a serious problem. Huge processing buffers are
> not very useful in practice.

Actually, they're directly harmful most of the time!

For any graph with more than one plugin, and with plugins that use 
internal buffers of the I/O buffer size, large buffers means you'll 
get a gigantic cache footprint. It gets worse in "high" latency real 
time situations (games, media players etc), where you have other 
threads fighting for the cache as well.

Obviously, this effect is less visible with non-trivial plugins - but 
even how many plugins in a "normal" graph are actually CPU bound? In 
my experience, the effect is very pronounced (several times higher 
CPU load with 512 samples/buffer than with 32) when using a bunch of 
sampleplayer voices (cubic interpolation + oversampling) and some 
simple effects. You have to do some pretty serious processing to go 
CPU bound on a modern PC...

//David Olofson - Programmer, Composer, Open Source Advocate

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