Description of problem:
"We just ran into a case where the openvswitch agent (local dev destack, current master branch) eats 100% of CPU time.
Pyflame profiling show the time being largely spent in neutron.agent.linux.ip_conntrack, line 95.
The code around this line is:
The documentation of eventlet.spawn_n says: "The same as spawn(), but it’s not possible to know how the function terminated (i.e. no return value or exceptions). This makes execution faster. See spawn_n for more details." I suspect that GreenPool.spawn_n may behave similarly.
It seems plausible that spawn_n is returning very quickly because of some error, and then all time is quickly spent in a short circuited while loop."
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Deploy a RDO openstack cloud (queens)
2. execute the "top" command
3. neutron-openvswitch will use 100% of cpu time (compute and nodes)
neutron-openvswitch uses 100% cpu time
neutron-openvswitch does not use 100% cpu time
The fix is in upstream stable/queens as of April 5th: