[opus] AM335x ARM Cortex-A8 performance drop opus 1.1

[Gregory Maxwell]

On Fri, Oct 18, 2013 at 2:21 PM, Jean-Marc Valin <jmvalin at jmvalin.ca> wrote:
> Just to clear things up... So 1.1 has some new analysis code that
> increases the amount of CPU. When building as floating point (which you
> appear to be doing, right?), the new code is enabled at complexity 7 and
> up (opusenc defaults to complexity 10 IIRC). This is why you've been
> seeing an increase in the CPU time. In version 1.0.x, complexity 5-10
> are the exactly the same for music. Running version 1.1 at complexity 5
> should be slightly faster than 1.0.x.
>
> When it comes to fixed-point, things are similar except that the
> threshold at which the new analysis code is enabled is complexity 10.
> This is because the new code uses floating-point instructions, even for
> a fixed-point build.

Adding to this, on cortex a8 a fixed point build will be faster.