I upgraded to Ubuntu 16.04 and started my iibench client.
https://github.com/mdcallag/mytools/blob/master/bench/ibench/iibench.py

I immediately get this warning.
/usr/lib/python2.7/dist-packages/pymongo/topology.py:74: UserWarning: MongoClient opened before fork. Create MongoClient with connect=False, or create client after forking. See PyMongo's documentation for details: http://api.mongodb.org/python/current/faq.html#using-pymongo-with-multiprocessing>
"MongoClient opened before fork. Create MongoClient "

Then I read the FAQ including this:
http://api.mongodb.com/python/current/faq.html#using-pymongo-with-multiprocessing

My code doesn't call fork, but it uses multiprocessing which calls fork for me. The new rules for PyMongo are extremely limiting. I have to do all my calls to fork and multiprocessing.Process up front. Imagine if I had to do all of my database queries at process start. What if I want to make occasional calls to multiprocessing.Process as my program runs? I can't do that given the new limits.

Can I get a version of PyMongo that doesn't have so much value added under the covers so I can use multiprocessing without these limits?