[Mesa-dev] mesa: Kill _ReallyEnabled, improve _mesa_update_state() performance.

[Matt Turner]

On Thu, Apr 24, 2014 at 5:50 PM, Eric Anholt <eric at anholt.net> wrote:
> Here's a series I got built when profiling to see why glamor's FBO cache
> is necessary.  It turns out the worst spots in the no-cache profile were
> present even with the cache, and they were about walking the 96 texture
> units we've got these days.  Thanks to Chris Forbes's
> _MaxEnabledTexImageUnit, I now found a way to cut down how much we walk,
> for a big performance win: -6.50518% +/- 2.55601% effect on runtime of the
> test (n=22).  And, along the way, I got to kill a couple of bitfields that
> I've always found confusing, and I bet others have as well.
>
> There's still a similar problem with glDeleteTextures() though -- if i
> don't use the FBO cache, then we spend 5% of CPU walking the array then.
> Anyone have nice ideas for improving that?  I'm thinking of just having a
> _MaxBoundTexImageUnit, but maybe there's something better.

I'm not really familiar with the code, so I only feel comfortable
giving R-b for 1-12 after a single pass. 1-12 are:

Reviewed-by: Matt Turner <mattst88 at gmail.com>