[fpc-pascal] Optimal number of threads for SMP

[Marco van de Voort]

In our previous episode, Graeme Geldenhuys said:
> > My rule of thumb is physical cores + a percentage. (like 10-20%).
> 
> Tell that to most developers out there, they clearly don't know that
> "rule of thumb". :-)  Mozilla Thunderbird under Win7 shows 47 threads.
> EditPad Pro 7 shows 18 threads. etc etc... I only have a mere dual-core
> system.

Not all thraeds are about increasing performance. Usually threads are just
to do (or monitor) things asynchroniously.

IOW, this is the about guestimating optimal threadcount if you divide one
task over multiple threads.  The point is that this is often not equal to
the number of hardware threads.