Hi,
I've been seeing issues with 4.7-rc kernels with some of our
multi-thread test cases. I've bisected it down to this commit:
commit 71d8c47fc653711c41bc3282e5b0e605b3727956
Author: Pablo Neira Ayuso <pa...@netfilter.org>
Date: Sun May 1 00:28:40 2016 +0200
netfilter: conntrack: introduce clash resolution on insertion race
.. and verified that reverting the commit restores the expected behaviour.
The test spins up 30 threads that start communicating simultaneously
with a server at the same target port, using a UDP based protocol over
loopback. This test is known to easily trigger the insertion race
that the commit is trying to fix - we check for EPERM errors and retry
in that case.
On my usual test rig the test gets about 700Mb/s. On current
mainline, the result alternates between a somewhat normal number,
something much lower (~150Mb/s), or complete failure following an
internal timeout.
Any thoughts on what may be going on?
Thanks,
Marc
