Dynamic Closure + Lazy Arguments = Performance Killer?

[Jason House]

I ported some monte carlo simulation code from Java to D2, and performance is horrible.

34% of the execution time is used by std.random.uniform. To my great surprise, 25% of the execution  time is memory allocation (and collection) from that random call. The only candidate source I see is a call to ensure with lazy arguments. The memory allocation occurs at the start of the UniformDistribution call. I assume this is dynamic closure kicking in.

Can anyone verify that this is the case?

600000 memory allocations per second really kills performance!