A special Rendezvous that works on subsets of processes in the parallel model

Question

I have a parallel model test that works great on 14 UUTs so far, but now I must write some sequences where the processes have to share hardware two at a time. I need to pair up the processes like (0,1), (2,3), (4,5), etc. and have a Rendezvous operate on them two at a time like this:
Processes (0,1) operate in parallel.
Processes (2,3) operate in parallel.
Processes (4,5) operate in parallel.
And so on....
Given enough time, maybe I could write that programmatically in TestStand; but I hope TestStand has a built-in Rendezvous for subsets of processes, or something else to do that. Does such a thing exist?

Answer 1

bmihura wrote:
OK I tried your pairing up idea with six processes (three seperate Rendezvous, one for each pair), but they all still ran in parallel. I'd like for one pair to execute at a time while locking out the others. This is because my system has two electronic loads (and two of many other things) that the six UUTs must share.
Ok, then what you proposed before (a separate rendezvous for each pair of threads) is not the correct way to synchronize things. A rendezvous just causes threads to block until the specified number of threads reaches the rendezvous point. You have three independent pairs of threads running in parallel. If that is not what you want, then using rendezvous like this isn't the right approach.
Please describe in more detail the entire flow of execution you are looking for. At what scope do you want the other threads to be blocked? Do you want each pair of threads to run all tests before any other threads can run? Do you want this only around certain steps? or Group of steps? Also, why do you want the threads to be paired? The most straightforward way I can think of to allocate two of a resource is to not care about which thread is using it, but to only allow two threads at a time, they don't necessarily have to be in pairs or even the same two threads every time. Do you really need the threads to be paired?
One of the simplest TestStand specific ways to allocate resources is to use the auto-schedule step types. They allow you to define blocks of code which require specific resources and then automatically run those blocks of code when those resources are available. I recommend you read the documentation for these step types and see if that sounds like it will work for you.
Another relatively simply way to synchronize access to a fixed number of resources among many threads is with a semaphore. A semaphore allows a certain number of threads through at a time, and blocks other threads until one of the ones using the resource release their acquisition of the semaphore. If the resources involved are more complicated though, I think you are better off using the auto-scheduler step types.
Hope this helps,
-Doug