Dynamic Closure + Lazy Arguments = Performance Killer?

[Bill Baxter]

On Sat, Oct 25, 2008 at 9:59 AM, Andrei Alexandrescu
<SeeWebsiteForEmail at erdani.org> wrote:
> Jason House wrote:
>>
>> 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!
>
> std.random does not use dynamic memory allocation.

Well the suggestion is that it may be using dynamic memory allocation
without intending to because of the dynamic closures.  Are you saying
that is definitely not the case?

> Walter is almost done implementing static closures.

Excellent!  So what strategy is being used?  I hope it's static by
default, dynamic on request, but your wording suggests otherwise.

--bb