[Mesa-dev] R600 tiling halves the frame rate

[Jerome Glisse]

On Tue, Oct 30, 2012 at 10:43 AM, Tzvetan Mikov <tmikov at jupiter.com> wrote:
> On 10/30/2012 07:12 AM, Patrick Baggett wrote:
>> Is your screen refresh rate 70 Hz? Because if so, that means that it's
>> syncing to the vblank on Mesa, and not doing so on the proprietary one.
>
> Unfortunately no. In fact the Gallium EGL/R600 doesn't support flip on
> vsync at all - eglSwapInterval is always 0. The output is a standard
> 60Hz LCD, plus I do get different, (but still low in absolute terms)
> frame rates with different chips. Off the top of my head:
> - HD5430 - 120 FPS
> - HD6450 - 140 FPS
> - HD6460 -  70 FPS
> - HD6750 - 400 FPS
> - HD6760 - 240 FPS
>
> I do think there is something fishy with the page flip though, which I
> am planning to investigate today. It is way too slow - a render loop
> which does nothing but a eglSwapBuffers() (no actual rendering
> whatsoever) runs at only 350 FPS. It should be either 60FPS, or thousands.
>
> regards,
> Tzvetan
>

So tested, it's something inside egl that lead to this, same program
as yours with glut on X11 with 2d tiling enabled and 2d color tiling
have a slight advantage 140fps vs 137fps (windowed so there is a blit
which would account for a hugue chunk of perf diff with fglrx).

However using egl i got 70fps with color tiling and 74fps without. So
something in egl is slowing things down.

Cheers,
Jerome