Re: [LAD] "enhanced event port" LV2 extension proposal

From: David Olofson <david@email-addr-hidden>
Date: Wed Nov 28 2007 - 17:52:21 EET

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

.------- http://olofson.net - Games, SDL examples -------.
| http://zeespace.net - 2.5D rendering engine |
| http://audiality.org - Music/audio engine |
| http://eel.olofson.net - Real time scripting |
'-- http://www.reologica.se - Rheology instrumentation --'
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Received on Wed Nov 28 20:15:06 2007

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