The original developer of the BSD port (Gaetano Catalli) also implemented a threaded version of the userspace datapath to increase performance. As with the original port, the threading work was done against Open vSwitch 1.1.0pre2. Giuseppe Lettieri and I have ported it forward, and it's functional and generally passes unit tests (with a few caveats). The threaded datapath has shown about 10x improvement in throughput in some tests, when compared to the current userspace datapath.
There are still a few issues to work through, but I wanted to present the patch now for discussion of the general approach. The threaded patches are available in the bsd-port-threaded branch in this repo: https://github.com/emaste/openvswitch/tree/bsd-port-threaded Or as a diff: http://people.freebsd.org/~emaste/openvswitch/threaded.diff The patch introduces a configure option to enable threaded mode: --enable-threaded, and the changes are largely confined to #ifdef THREADED blocks. Two mutexes are added to dp_netdev: one for the flow table, and one for the port list. (I've also added a mutex over most of lib/vlog.c, although a less conservative approach may be possible.) Significant outstanding issues are: 1. Buffer ownership and management isn't really correct right now, apparently done due to a desire to avoid extra copies. This seems to be a consequence of the standard BPF / libpcap interface. 2. The patch needs a better method of ensuring flows aren't deleted while there may be a reference in the datapath thread. 3. The datapath thread waits in poll() with each port's file descriptor in the fd array. However there's currently no fd to signal a bridge reconfiguration, so the poll() has to timeout before the thread will pick up the new config on the next time through its loop. In any case, I wanted to post the current patch for discussion and review while working on the remaining issues. I'm very interested in your thoughts and comments. -Ed **
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