Comment 13 for bug 1194026

Reviewed: https://review.openstack.org/36890
Committed: http://github.com/openstack/neutron/commit/57e1fa32648a28ae83e3c3033258fe08de2e5fca
Submitter: Jenkins
Branch: master

commit 57e1fa32648a28ae83e3c3033258fe08de2e5fca
Author: Nachi Ueno <email address hidden>
Date: Fri Jul 12 12:21:46 2013 -0700

    Improve l3-agent performance and prevent races in it.

    Fixes bug 1194026
    Fixes bug 1200749

    Introduce a looping call for performing synchronization with
    neutron server.
    The sync will be performed only if router changes are notified
    via rpc. Only affected routers will be synchronized.

    Changes will be implemented by the l3 agent spawning a
    distinct greenthread for each router - iptables will
    be executed only once using iptables_manager.defer_apply_on.

    This patch will prevent the occurence of the following issues:
    - Out-of-order rpc message processing
    - Long processing time for router changes due to serial execution
    - Occasional and expected RPC blocks for long periods
    - Unnecessary processing of multiple requests

    Change-Id: I0978d1c38ac5c38c4548e5b1877857bb5cac3b81