(mpich 3.2)

I have a scenario when i add a few extra processes do existing intercom.

it works as a simple loop -- 

(1) n processes accept on n-intercom

(2) 1 process connects 

(3) intracom is merged into n+1 intercom, intracom and n-intercom are closed

(4) repeat 1-3 as needed.

Occasionally, i observe that step 3 spuriously locks up (once i get in the range of 100+ processes). From what i can tell, all processes in step 3 are accounted for, and are waiting on the merge, but nothing happens. the collective barrier locks up.

I really have trouble resolving this issue, any ideas are appreciated!

Thank you very much.

-Dmitriy