thorsten.i.r...@jyu.fi wrote:
> I've just spent a session optimizing performance of the weather dynamics
> routines, and I have largely done so by analyzing the performance of
> elementary Nasal function calls and making use of my findings (and also by
> dispensing with the pretense of elegant coding).
>
> I was rather gratified to see the framerate improve significantly - a test
> configuration which used to render at ~20 fps is now blasting away at ~60
> fps. Given that I achieve only ~75 fps for the same cloud configuration if
> I don't move any clouds, that's probably quite good already. In practical
> terms, I usually get now above a comfortable 30 fps with the F-14b in a
> drifting noon population of Cumulus clouds.
>
> This almost miraculous increase was to a good part achieved by
> consistently banning any use of the props or geo classes from
> performance-critical code. To give an example - it turns out that while
>
> node = props.globals.getNode("test",1);
> for (var i = 0; i < n; i = i +
> 1){node.getChild("array",i,1).getNode("test",1).setValue(value);}
>
> is an elegant structure to initialize or write an array of properties in
> the tree, the ugly variant
>
> for (var i = 0; i < n; i = i + 1){setprop("test/array["~i~"]/test", value);}
> is ten (!) times faster. Basically, replacing an instance of a props
> method with getprop() or setprop() seems to give at least a factor 2 in
> speed, often more.
>
After thinking about it I think that in the second case the property
tree is being walked trough by the C++ code while in the first case it's
done in Nasal. You just discovered that Nasal is 10x slower than C++ code!
This is exactly why I prefer core code to end up in C++ in the end.
That said, Nasal performance tests are always useful.
Erik
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