[LAD] vectorization

Fons Adriaensen fons at kokkinizita.net
Mon May 5 20:33:10 UTC 2008

On Mon, May 05, 2008 at 07:18:39PM +0200, Jens M Andreasen wrote:

> Could you try this out with your proposed compiler options on your own
> hardware?
> ...
> #define N 1024
> ...
> int n = 1000000;
> ...

Looping a million times over the same small data vector
is _not_ very realistic. 

In a real app, the data size would be much longer (there's
no need to optimise otherwise), that data would be rewritten
for each iteration (no need to redo the calculation otherwise),
and the work would not be done in a single long run but be
divided over a number of e.g. jack process callbacks.

I've again performed some tests on zita-convolver used by
jconv to do the York Minster config. That means around 240
different blocks of 8192 complex values each. The differences
between plain C++, hand vectorized, and optimised assembly
code are absolutely marginal in that case.



Laboratorio di Acustica ed Elettroacustica
Parma, Italia

Lascia la spina, cogli la rosa.

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