Maximum number of generated parallel loops

[jsiegel]

Why is the number of generated parallel loop instances for a For loop (in the For Loop Iteration Parallelism dialog) limited to 64?  LabVIEW can handle more than 64 parallel threads, can't it?  I will have a machine with 104 cores--will two For loops each configured to generate 52 parallel loop instances give the results that I want (i.e., 104 parallel executions of my VI)?  Will a (non-parallelized) For loop opening my VI in call and collect mode 104 times give me the same results?  Is a parallelized For loop containing a call to a single VI any different from calling the VI with call and collect inside a For loop?

[altenbach · Accepted solution]

You can change it to allow up to 256 parallel instances by adding an entry to the labview.ini file.

ParallelLoop.MaxNumLoopInstances=256

(See also)

[jsiegel]

Thanks, altenbach, for that information!  So the limit of 64 is not a fundamental limit of the For loop and is there just to protect us.

Still, I'm still curious--is doing multiple call and collects the same as running a parallelized For loop?  Is there some optimization in the parallelized For loop that can't be had with the call and collect method?