docs: Document that hw-offload is experimental.

Currently, the set of flows that may be offloaded is very small compared
to the overall capabilities of the OpenFlow support in OVS. In the
majority of cases, if a user attempts to enable this flag they are
unlikely to observe a performance increase, because for instance they
lack the correct hardware; lack the correct kernel version; or their
flow tables are too complex for the hardware to handle.

To moderate expectations around this feature, describe it as
experimental. Over time, we expect that the functionality and usefulness
of this feature will grow and we should be in a better shape to revisit
the status of this functionality after it has had some time to mature.

Signed-off-by: Joe Stringer <[email protected]>
Acked-by: Simon Horman <[email protected]>
Acked-by: Flavio Leitner <[email protected]>

NEWS

@@ -65,7 +65,7 @@ Post-v2.7.0
      * Transparently pop and push Ethernet headers at transmit/reception
        of packets to/from L3 tunnels.
    - The BFD detection multiplier is now user-configurable.
-   - New support for HW offloading
+   - Add experimental support for hardware offloading
      * HW offloading is disabled by default.
      * HW offloading is done through the TC interface.
 

vswitchd/vswitch.xml

@@ -192,6 +192,11 @@
         <p>
           Currently Open vSwitch supports hardware offloading on
           Linux systems.  On other systems, this value is ignored.
+          This functionality is considered 'experimental'. Depending
+          on which OpenFlow matches and actions are configured,
+          which kernel version is used, and what hardware is
+          available, Open vSwitch may not be able to offload
+          functionality to hardware.
         </p>
       </column>