On Thu, Jun 11, 2015 at 09:43:59AM -0700, Neil McKee wrote: > Packets are still sampled at ingress only, so the egress > tunnel and/or MPLS structures are only included when there is just 1 output > port. The actions are either provided by the datapath in the sample upcall > or looked up in the userspace cache. The former is preferred because it is > more reliable and does not present any new demands or constraints on the > userspace cache, however the code falls back on the userspace lookup so that > this solution can work with existing kernel datapath modules. If the lookup > fails it is not critical: the compiled user-action-cookie is still available > and provides the essential output port and output VLAN forwarding information > just as before. > > The openvswitch actions can express almost any tunneling/mangling so the only > totally faithful representation would be to somehow encode the whole list of > flow actions in the sFlow output. However the standard sFlow tunnel > structures > can express most common real-world scenarios, so in parsing the actions we > look for those and skip the encoding if we see anything unusual. For example, > a single set(tunnel()) or tnl_push() is interpreted, but if a second such > action is encountered then the egress tunnel reporting is suppressed. > > The sFlow standard allows "best effort" encoding so that if a field is not > knowable or too onerous to look up then it can be left out. This is often > the case for the layer-4 source port or even the src ip address of a tunnel. > The assumption is that monitoring is enabled everywhere so a missing field > can typically be seen at ingress to the next switch in the path. > > This patch also adds unit tests to check the sFlow encoding of set(tunnel()), > tnl_push() and push_mpls() actions. > > The netlink attribute to request that actions be included in the upcall > from the datapath is inserted for sFlow sampling only. To make that option > be explicit would require further changes to the printing and parsing of > actions in lib/odp-util.c, and to scripts in the test suite. > > Further enhancements to report on 802.1AD QinQ, 64-bit tunnel IDs, and NAT > transformations can follow in future patches that make only incremental > changes. > > Signed-off-by: Neil McKee <neil.mc...@inmon.com>
Neil, would you mind posting a new version of this patch rebased against current master? I'll review it next week. Thanks, Ben. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
