On Tue, May 12, 2015 at 10:21:19AM +0200, Duarte Nunes wrote: > We've observed that for high flow setup rates, the flow table becomes a > bottleneck since it only allows a single writer (all CRUD flow operations > take the ovs_mutex). > > A solution for this is to shard the flow table. A hash function is used to > know which table to query on packet ingress and on recirculate as well as > to know on which table to CRUD a flow. Some bits off the flow ID are used > to identify the shard. The number of shards is configured upon datapath > creation.
First, I'm surprised to see high flow setup rates since the introduction of megaflows. Generally, megaflows greatly reduce the flow setup rate. Second, is it possible to use a better data structure? Perhaps one could, for example, use a mutex per hash chain, instead of a single mutex, or per-CPU data structures. Ideally, if the data structures were improved, then one would not need to change the datapath interface at all. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
