Thorsten Froehlich wrote:
> On 06.02.10 07:40, waggy wrote:
>> I'm guessing the extra switching cost is more than offset by keeping
>> the floating-point pipelines full.
> 
> Your guess is wrong as long as you counted "cores" as the logical number 
> of cores seen by the operating system - including simultaneous 
> multi-threading capabilities your processor may have.
> 
I'm counting the eight physical cores in the two quad-core AMD 2344 HE 
sockets F on the motherboard.

> What you are most likely seeing is that your OS gives your application 
> slightly higher priority as a whole if it is running more threads, 
> either because it is designed to detect compute-heavy applications or 
> because its internal scheduling is on a thread rather than process basis.
> 
Interesting.  This is a on recent install of Ubuntu 9.10 Server Edition 
with their "server" kernel.  I'll do some better timing tests after I 
set up another one of these boards headless.

~David

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