Once the next validate_all has completed on the communicator you know the previous one completed, so you only ever need to keep track of one old validate_all per communicator. -d On Apr 29, 2011, at 11:08 AM, Solt, David George wrote:

I was also thinking about whether I can verify if/when a rank will no longer be called upon to participate in a termination protocol, but that can wait till later and may not actually be important for us.