Disappointing math performance compared to GDC

David Nadlinger via digitalmars-d-ldc digitalmars-d-ldc at puremagic.com
Wed Oct 8 10:31:19 PDT 2014


Hi,

On Wednesday, 8 October 2014 at 07:37:15 UTC, Gabor Mezo wrote:
> There is a number crunching benchmark in it that doing a simple 
> gradient descent learning on a small multilayer perceptron 
> neural network. The core of the benchmark is about some loops 
> doing basic computations on numbers in float[] arrays (add, 
> mul, exp, abs).

Would it be possible to publish the relevant parts of the code, 
i.e. what is needed to reproduce the performance problem? I'm 
currently working on a D compiler performance tracking project, 
so real-world test-cases where one compiler does much better than 
another are interesting to me.

If the code is proprietary, would it be possible for or me 
another compiler dev to have a look at the code, so we can 
determine the issues more quickly?

> DMD 2.066 -O -release -inline -boundscheck=off : 0.06 secs
> LDC2 0.14 -O3 -release                         : 0.051 secs

Note that array bounds checks are still enabled for LDC here if 
your code was @safe.

David


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