[ovs-git] [openvswitch/ovs] 182c78: stp: Fix stp tests and make them more stable.

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/openvswitch/ovs
  Commit: 182c78216cd2a8326e5053b5c5940293d5ac06a9
      https://github.com/openvswitch/ovs/commit/182c78216cd2a8326e5053b5c5940293d5ac06a9
  Author: nickcooper-zhangtonghao <nic at opencloud.tech>
  Date:   2017-03-27 (Mon, 27 Mar 2017)

  Changed paths:
    M tests/stp.at

  Log Message:
  -----------
  stp: Fix stp tests and make them more stable.

The difference between machines may cause the test to fail.
More importantly, when topology is changed or the root brdige
receives the TCN BPDU, the root bridge will start the topology
change timer. We should wait the topology change timer to stop
after 35s (max age 20 + forward delay 15). After 35s, the root
bridge will stop send CONF BPDU with STP_CONFIG_TOPOLOGY_CHANGE
flag and the topology will be stable. During this time, we should
make time warp (in a second) because the hold timer of stp ports
will stop after 1s. Then the root bridge can send quickly topology
change ack (other bridges may send TCN BPDU to root bridge) for
avoiding root brdige to flush fdb and mdb frequently.

This patch has been tested on centos 7.2 (kernel 3.10.0, python
2.7.5 and gcc 4.8.5), ubuntu 16.04 (kernel 4.4.0, python 3.5.2
and gcc 5.4.0) and ubuntu 16.04 (kernel 4.10.4, python 3.5.2 and
gcc 5.4.0). This patch has been tested for 3 hours. This patch
may make the stp tests more stable.

[Committer notes]

Folded time/warp execution into a for loop.

Fixes: 427e9751f300 ("tests: Add and improve stp tests.")
Reported-at: http://paste.ubuntu.com/24215426
Reported-at: https://mail.openvswitch.org/pipermail/ovs-dev/2017-March/330032.html
Signed-off-by: nickcooper-zhangtonghao <nic at opencloud.tech>
Acked-by: Alin Gabriel Serdean <aserdean at cloudbasesolutions.com>
Signed-off-by: Joe Stringer <joe at ovn.org>