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

[Keith Whitwell <keith at tungstengraphics dot com>]

Ian Romanick wrote:
> 
> On Thu, May 16, 2002 at 03:41:32PM -0700, Gareth Hughes wrote:
> 
> > I would like to propose a small change to the pthread_descr structure in
> > the latest LinuxThreads code, to better support OpenGL on GNU/Linux
> > systems (particularly on x86, but not excluding other platforms).  The
> > purpose of this patch is to provide efficient thread-local storage for
> > both libGL itself and loadable OpenGL driver modules, so that they can
> > be made thread-safe without any impact on performance.  Indeed, using
> > this mechanism, an OpenGL driver can ignore the difference between
> > running with a single thread and running with multiple threads, as
> > "global" data will be accessed in the same way independent of the number
> > of threads running.
> 
> Please forgive my lack of understanding of the relevent issues.  It seems to
> me that this issue (or a closely related issue) has been brought up in the
> past, and was brutally slain by Linus.  Admittedly, a lot has changed in the
> Linux world in 2+ years, but could someone explain how this proposal relates
> to this earlier request:
> 

That's quite a different approach, and really overkill -- libGL doesn't need
whole different virtual memories per thread, just a quick way to get two
pointers.  The thread-local storage already exists and is laying unused...

Keith