Re^3: Parallelization of multiple nested loops

[salva]

There may be at most 6 processes running in parallel. But my numbers refer to the total number of processes created and destroyed during the complete computation.

My point is that starting and stopping processes have a non insignificant overhead. If you start too many the total cost of forking may be an important percentage of the total cost of the computation.

[hippo]

Quite. If my reading of biosub's code (and my maths) is correct it forks 6^12 times (2,176,782,336 times). That's a tonne of overhead.