Add a "Performance" FAQ category. So far the only entry addresses the
issue with using a new kernel module with an older (pre-megaflows)
userspace.
Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
---
FAQ | 21 +++++++++++++++++++++
NEWS | 5 +++++
2 files changed, 26 insertions(+)
diff --git a/FAQ b/FAQ
index cd3241a..4a8a5be 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 43a2079..6e69d2a 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
--
1.7.10.4
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