[Mesa-dev] Reducing get.c size (and get_es1.c and get_es2.c)

[Kristian Høgsberg]

2010/5/6 Kristian Høgsberg <krh at bitplanet.net>:
> Hi,
>
> Ok, I suppose this is not the most pressing issue in mesa, but I was
> toying with an idea of how to reduce get.c size and integrate
> get_es1.c and get_es2.c and I had to try it out.  Of course it ended
> up being a bigger project and took a couple of days, but in the end I
> think it turned out to be a worthwhile effort.  The result is the two
> patches on the get-optimagix branch in my personal mesa repo:
>
>  http://cgit.freedesktop.org/~krh/mesa/log/?h=get-optimagix

I've updated the patch on the branch here, but I'm still not going to
send it to the list (it's 500k and most of which deletes generated
code).  But I've been going back and forth with Brian about the patch
a few times and we found a few bugs and made the code a little faster.
 Brian cooked up a small micro-benchmark for the glGet*v() functions
and it turned out that the code was actually slower than the old
generated code.  With a little tweaking of the table lookup and adding
a couple of likely() annotations, I got the code from 30s to 23s,
where the old code would take 15s.  That's still 17 million gets per
second, so I doubt the new code is going to be a bottleneck.

Kristian