On Tue, May 28, 2013 at 11:38 AM, zuo <zu...@163.com> wrote: > Hi, > Recently I read the code of OpenvSwitch (version 1.9) to learn how packet is > processed in datapath and userspace. However, there are some issues that I > didn’t understand clearly. Can anybody help me? > (1) When the first packet of a flow comes to the datapath, the datapath > transmit it to the userspace using netlink. Does the datapath buffer the > packet? Or it is just buffered in userspace?
There's no buffering in the kernel. > (2) As the comment of facet introduces, facet is exact-match flow in > userspace and subfacet is also exact-match flow in datapath, Can anybody > take an example for that one facet has more than one subfacet? If the kernel's definition of a flow is more precise than userspace's. > (3) When the packet comes to the userspace, it is transmited to the > controller. However, as my comprehension, before the flow_mod message comes > from the controller, it will create a facet in userspace and corresponding > subfacet action in SF_fast_path of datapath, so what is the action of the > SF_fast_path flow entry? Is it to the userspace or directly to the > controller? Userspace makes all connections to the controller, the kernel never sends packets directly. > (4) It seems that datapath flow entry is 5 seconds time-out, then how > soon is the facet time_out? Where can I find the code of time_out? Facets timeout when all subfacets have been removed. > (5) I found that every time it could handle 50(max_batch) upcalls every > time? When the traffic in production network is huge, isn’t it small? This just allows other things a chance to run. _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
