[compiz] Nvidia performance bug and vterm switching bug

[dragoran]

okasion wrote:
> This has been a long problem with Compiz that NVIDIA never fixed,
> intermittent performance problems such as hick ups; the problem is easily
> reproducible moving the cursor while opening programs such as Firefox or
> Evolution.
> Until Compiz 0.3.4 this bug was fixed setting the __GL_YIELD environment
> variable to "NOTHING" in Compiz environment.
the only thing that this changes (and is supposed to change) is to make 
compiz responsive under high cpu load.
> Since Compiz 0.3.6 setting the __GL_YIELD environment variable to 
> "NOTHING"
> is not enough, but launching Compiz WITHOUT "--unredirect-rendering" 
> is also
> needed to fix this. So whats the problem using direct-rendering? using
> direct-rendering triggers the NVIDIA vterm switching bug, that makes the
> screen keep black on vterm switching. If one clicks at the black 
> screen, a
> hard reboot is needed; the only solution is to kill X and start it again.
Turn of sync to vblank this might be causing this.
> Also, for some people like me, using --indirect-rendering gives better
> performance than using direct rendering.
no its not!
if you use indirect rendering on nvidia the _GL_YIELD env variable will 
gets ignored and the system will be almost unuseable under high load.