On 27.02.2005, at 15:19, Sven Neumann wrote:

It is called once per tile. Your approach probably makes sense as long
as don't use g_rand_new() but g_rand_new_with_seed().  g_rand_new()
initializes the random number generator from /dev/urandom which is
probably too expensive to be done once per tile.

Not too bad, here are the results (Patch in different mail):

Before:
Linear Gradient blend on a 3000x3000 pixel image (Dithering on)
1 processor:            7.2 s
2 processors:           8.9 s

Linear Gradient blend on a 3000x3000 pixel image (Dithering OFF)
1 processor:            2.5 s
2 processors:           1.5 s

After Linear Gradient blend on a 3000x3000 pixel image (Dithering on) 1 processor: 7.0 s 2 processors: 3.6 s

Linear Gradient blend on a 3000x3000 pixel image (Dithering OFF)
1 processor:            2.6 s
2 processors:           1.4 s

The degradation in the 1 processor setting without dithering
seems to be a small measurement fluke in my last round since
I consistently get better times in all other cases. Apologies
for that.

I need to think about a larger test image since its starting
to get too difficult to time this microbench...

Servus,
      Daniel

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