Subject: Re: [linux-audio-dev] changing control port values with LADSPA: a serious issue?
From: Jake Donham (jake_AT_bitmechanic.com)
Date: Sun Mar 17 2002 - 01:11:43 EET
"David" == David Olofson <david_AT_gardena.net> jots:
David> 1) Simple operations are memory bound on modern machines.
David> 2) Using more buffers increases cache footprint, and thus
David> increases the number of cache misses.
David> 3) If there is heavy work going on in the background,
David> there's a big chance the audio and control buffers
David> will be thrown out - which results in increased use
David> of memory having a *much* harder impact on
David> performance.
Interesting.
Does this not apply to the instruction cache as well--that is, if you
touch less memory at the cost of increasing the code size of all
plugins (which must now include interpolation code) have you really
won? Depends on how much extra code, and how big your buffers.
>> It doesn't seem like a good idea to hard-code particular kinds
>> of parameter interpolation, linear or otherwise.
David> You have to consider the cost of any conditional code in
David> plugins and hosts - and not only the complexity, but also
David> the cost of pipeline flushes when branches are
David> mispredicted...
Right, that's why I was suggesting a separate control buffer, so
plugins wouldn't have to do any extra computation.
Jake
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