[Dri-devel] Re: OpenGL and the LinuxThreads pthread_descr structure

[Gareth H. <gar...@ac...>]

Jakub Jelinek wrote:
> Hi!
> 
> What percentage of applications use different dispatch
> tables among its threads? How often do dispatch table changes
> occur? If both of these are fairly low, computing a dispatch table
> in an awx section at dispatch table switch time might be fastest

I should also point out that display list compilation and playback is 
another place where the dispatch table changes (typically, you have at 
least a dispatch table for regular immediate mode, display list 
compilation and display list playback).  One of the ugliest things about 
the Microsoft Windows implementation of OpenGL is that the driver 
backend must call a function to register a new dispatch table, and the 
OpenGL library then makes several copies of this table internally. 
Being able to switch dispatch tables with a single pointer reassignment 
makes it easy to do very powerful optimizations.

-- Gareth