[cairo] [PATCH] cairo-gl: Make VBO size run-time settable

[Bryce W. Harrington]

On Thu, Aug 29, 2013 at 11:20:57AM +0100, Chris Wilson wrote:
> On Thu, Aug 29, 2013 at 06:34:11AM +0000, Bryce W. Harrington wrote:
> 
> You want to actually explain why you want to do this here, your cover
> letter would be ideal content for the changelog.
> 
> > Signed-off-by: Bryce Harrington <b.harrington at samsung.com>
> 
> I think this should be a property of the ctx. A second patch could even
> add _cairo_gl_debug_set_vbo_size() if you found that useful. A third
> patch might set different values for gl vs egl, based on your results
> above.
> -Chris

Chris, btw, sort of an aside question...

As I've been running various performance tests for each of the GL
compositors, I am noticing that spans and traps basically have identical
performance (any differences are in the noise).  I'm aware of the
implementational differences between the two, and I've expected to see
spans perform better than traps on at least a few of these tests, but
nothing so far.  I'm guessing the tests simply aren't exercising spans'
talents, or I'm not running the right tests.

Can you explain to me why traps and spans are both provided as options?
Why would a user prefer to select one over the other?

Bryce