I've just run into a "feature" of the LV2009 Parallel For Loops which
is a bit of a nuisance! The number of loop instances is determined by
two values: 1) the number of instances in the Configure Iteration
Parallelism dialog, and 2) the number wired to the P terminal of the
loop. It turns out that the number of instances created is the smaller
of these two.
The nuisance is that if I wire the number of
processors from CPU Information to P (as recommended) then when my new
16-core machine arrives (I wish!) I don't get that benefit unless the
dialog value is also >= 16. And the 64-core machine that arrives
next requires the dialog value to be reset in every Parallel For Loop -
or I set it to be some unreasonably large number now, and therefore it's
pretty much meaningless.
My suggestion is that the default number of instances set in the dialog is "Maximum" - i.e. it will use the maximum number of processors available. It should still be able to be set lower should the programmer wish to restrict the number below that. Then the default case works transparently as the programmer would usually want without needing to wire from CPU Information, and there are no surprises down the track when loops don't speed up on a new machine as expected.