Flows failed to get install in the same openflow table when programmed from different Threads simultaneously.

When an openflow node connects to the controller, ovsdb's net-virt-provider bundle programs the switch with a set of pipeline flows (From Table 0 -> 110 in increments of 10, except Table 10 and 70). These pipeline flows are vital for openstack operation.

But, randomly some of the flows fails to get programmed. 1 of the cases that we narrowed down is on Table 0 flow. This randomness happens based on the timing of another flow being installed from another thread. This is the LLDP flow programmed by another thread. When these 2 threads happen to operate simultaneously (or almost), one of the flows gets lost somewhere in the system.

Actual flows programmed in OVS : https://gist.github.com/05b25649edd8ec6fa91c
[Table 10 and 70 will be missing and that is intentional]. Table 0 pipeline flow is missing.

The strangeness of the situation is that, the Table0 pipeline flow (DEFAULT_PIPELINE_FLOW_0) that is missing in the actual flow-table in OVS is seen in the config tree & operational tree.

Config : http://localhost:8181/restconf/config/opendaylight-inventory:nodes
=> https://gist.github.com/cef3a914ca18cb76e330

Operational : http://localhost:8181/restconf/operational/opendaylight-inventory:nodes => https://gist.github.com/bfc9e48b3d4fde91cb11