There are a couple of reasons why CP might only be running on one core at a time:
- It's a really old version of CP from before multiprocessing was added
- You're running from the command line rather than the interface- CP only "natively" multithreads in the interface.
- You're in the interface but in test mode (for which CP uses only one core because it's only processing one image)
- You're running in the interface AND in analysis mode, but CP is still analyzing the first image; CP runs the first image (which is just on one core), and once that successfully completes it deploys the rest of the workers across lots of cores.
If none of these are true, can you tell us more about your OS, CP version, setup, etc so we can try to figure out what the reason could be?