[maemo-developers] Performance of floating point instructions

[From: Eero Tamminen]

Hi,

ext Alberto Mardegan wrote:
> Right. Just to complete the picture, here's the same data with -O2:
> 
> float (fast mode enabled):
> map_path_calculate_distances: 40 ms for 8250 points
> map_path_calculate_distances: 2 ms for 430 points
> 
> double (fast mode enabled):

Note that fast mode affects only floats.


> map_path_calculate_distances: 93 ms for 8250 points
> map_path_calculate_distances: 4 ms for 430 points
> 
> (I'm not posting the same data with fast mode disabled, as it cannot be 
> worse than the -O0 case, which is anyway not too far from these values)
> The relative preformance seems to be about the same. But then of course, 
> it might not be because of the FPU, but of the data transfers.


	- Eero