Windows multi-threading performance issues on multi-core systems only

[Simen kjaeraas]

dsimcha <dsimcha at yahoo.com> wrote:

> This is a synthetic, extreme corner case benchmark, but I think it  
> hammers home
> the point that such problems are at least plausible.  Tested on a Core 2  
> Quad with
> -O -inline -release:
> Timing with affinity for all 4 CPUs:  28390 milliseconds
>
> Timing with affinity for only 1 CPU:  533 milliseconds

Tested this on a Core 2 Duo, same options. OS is Windows 7, 64bit. It  
scales roughly inverse linearly with number of threads:

163ms for 1,
364ms for 2,
886ms for 4

This is quite different from your numbers, though.

-- 
Simen