Parallel processing and further use of output

[John Colvin via Digitalmars-d-learn]

On Monday, 28 September 2015 at 12:18:28 UTC, Russel Winder wrote:
> As a single data point:
>
> ======================  anonymous_fix.d ========== 500000500000
>
> real	0m0.168s
> user	0m0.200s
> sys	0m0.380s
> ======================  colvin_fix.d ==========
> 500000500000
>
> real	0m0.036s
> user	0m0.124s
> sys	0m0.000s
> ======================  norwood_reduce.d ==========
> 500000500000
>
> real	0m0.009s
> user	0m0.020s
> sys	0m0.000s
> ======================  original.d ==========
> 218329750363
>
> real	0m0.024s
> user	0m0.076s
> sys	0m0.000s
>
>
> Original is the original, not entirely slow, but broken :-). 
> anonymous is the anonymous' synchronized keyword version, slow. 
> colvin_fix is John Colvin's use of atomicOp, correct but only 
> ok-ish on speed. Jay Norword first proposed the reduce answer 
> on the list, I amended it a tiddly bit, but clearly it is a 
> resounding speed winner.

Pretty much as expected. Locks are slow, shared accumulators 
suck, much better to write to thread local and then merge.