How to deal with the case that when one or some processes are much faster than others

Because of the essence of one-sided communication, the progress of different processes may vary a lot, especially under the heterogeneous environment. If simply write the code like
for e in range(epochs):
xxx
some_collective_ops

Then, the last collective ops will waste the advantage of one-sided communication. We need a better way to design the code or deal with this situation.