[Nouveau] "enable ctxprog xfer only when we need it to save power" introduces big performance regression

[Martin Peres]

Le 09/11/2011 23:10, Marcin Slusarz a écrit :
> For anyone who don't read IRC logs - it turns out it regressed only on 
> my box, because I have page flipping disabled (due to page flipping 
> being very buggy here, see 
> https://bugs.freedesktop.org/show_bug.cgi?id=42398), which forces gpu 
> context switch on every frame - even with (OpenGL) full screen apps. 
> And this patch slows down context switches. So, can we disable xfers 
> in ctxprog only when page flipping is enabled? Or is there any other 
> option? Marcin 
Hmm, it isn't logical yet. To test for performance regression, I 
launched the well known context switch test that is glxgears and only 
found a performance decrease of 1%.

I'll test with pageflip disabled though and see for myself.

Anyway, we'll do something about it. I just hope that most cards don't 
have this problem. This is clearly an hw regression.

Martin