Scalability in std.parallelism

[thedeemon]

On Monday, 24 February 2014 at 14:34:14 UTC, Russel Winder wrote:

> Two cores with hyperthreads generally means a maximum speed up 
> of 2 with optimized native code.

Not true. If the code is not trivial and the threads are not 
doing exactly same instructions (i.e. they can do some search 
where number of operations depends on data) then 2 cores x 2 
hyperthreads can easily provide more than 2x speed up (but far 
from 4x of course). I see it very often in my video processing 
code.