On Thu, 2007-05-10 at 18:48 +0200, Krzysztof Helt wrote:

Hi,

Below are tests of different scrolling methods for cards I have.

All tested drivers use SCROLL_REDRAW method. I forced SCROLL_MOVE 
method by adding flag FB_READS_FAST. 

Here are some conclusions:
Comparing two new methods: smart blitting and smart blitting with 
merge, the merge of blits gives some speed up at lower bit 
depths, but it is usually lost at higher ones. So we can choose 
both ways (with or without the merge).

The smart blitting is so much faster in many cases comparing to 
the current dump SCROLL_MOVE, that it can replace the current 
method. For some cards it is even faster than SCROLL_REDRAW with 
accelerated fb_imageblit().

The drivers tdfxfb and nvidiafb will benefit from switching to 
SCROLL_MOVE method if the smart blitting is added (the tdfxfb  
even without it). I wonder if Geforce cards also shows this speed 
up if switched to the SCROLL_MOVE method but I have no card to 
test.

The mach64 case is strange: it gives upper hand to smart blitting 
but not at 32-bit depth.

I will prepare a patch with drop-in replacement for current 
SCROLL_MOVE method without blits merging (it is the cleanest 
solution).

Nice benchmarks and results!

The test is done on cards with both accelerated imageblit and copyarea.
Do you get the same results in unaccelerated drivers (vesafb)?  

If you do, it might even be wise to change the default from
SCROLL_REDRAW to SCROLL_MOVE...?

Tony



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