On Fri, Apr 06, 2001 at 03:58:10PM +0200, Ernst Lippe wrote:
> > I don't know how large a tile is, but since IMHO the major impact of
> > blocking seems to come from the CPU cache, I suspect that is too big for
> > older CPUs. I have done the whirl&pinch blocking thing about three years ago
> > (and forgot to send the patch), and tried it on an Alpha21164 and a P5.
> I think you're looking in the wrong direction here. Similar to the
> bumpmap (see my other message) I strongly suspect that the tile-cache is
> too small.

For bumpmap, it is of course a tile cache problem, for whirl&pinch I'm not
sure, since the performance boost differed very much on the Alpha vs. P5
vs. Athlon depending on the blocking size. So I assume that the CPU cache
plays a major part.

> You can check this for yourself by profiling your code. I expect that
> there is hardly any difference in processor time between your version
> and the original but that there is an important difference in the number
> of calls to gimp_tile_get and gimp_tile_put. (Sorry, did not try that
> myself).

Ok, I will try that. I have no big knowledge of Gimp's internals, but that
seems preety easy to find out...

         Georg Acher, [EMAIL PROTECTED]         
          "Oh no, not again !" The bowl of petunias          
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