From bcb8bde4ca385b85154d3905ed7779473249e6fe Mon Sep 17 00:00:00 2001 From: Jarno Rajahalme Date: Wed, 13 Nov 2013 11:19:56 -0800 Subject: [PATCH] FAQ, NEWS: Notes on TCP flags matching. Add a FAQ categorry "Performance Problems". So far the only entry addresses the issue with using a new kernel module with an older (pre-megaflows) userspace. --- FAQ | 21 +++++++++++++++++++++ NEWS | 5 +++++ 2 files changed, 26 insertions(+) diff --git a/FAQ b/FAQ index cd3241a30..4a8a5beec 100644 --- a/FAQ +++ b/FAQ @@ -468,6 +468,27 @@ A: Open vSwitch uses different kinds of flows for different purposes: regardless of the type. +Performance +----------- + +Q: I just upgraded and I see a performance drop. Why? + +A: The OVS kernel datapath may have been updated to a newer version than + the OVS userspace components. Sometimes new versions of OVS kernel + module add functionality that is backwards compatible with older + userspace components but may cause a drop in performance with them. + Especially, if a kernel module from OVS 2.1 or newer is paired with + OVS userspace 1.10 or older, there will be a performance drop for + TCP traffic. + + Updating the OVS userspace components to the latest released + version should fix the performance degradation. + + To get the best possible performance and functionality, it is + recommended to pair the same versions of the kernel module and OVS + userspace. + + Configuration Problems ---------------------- diff --git a/NEWS b/NEWS index 1830e3e18..38e3d9d3f 100644 --- a/NEWS +++ b/NEWS @@ -1,5 +1,10 @@ Post-v2.0.0 --------------------- + - TCP flags matching: OVS now supports matching of TCP flags. This + has an adverse performance impact when using OVS userspace 1.10 + or older (no megaflows support) together with the new OVS kernel + module. It is recommended that the kernel and userspace modules + both are upgraded at the same time. - The default OpenFlow and OVSDB ports will change to IANA-assigned numbers in a future release. Consider updating your installations to specify port numbers instead of using the -- 2.47.0