On Thu, Oct 30, 2014 at 12:06:30PM +0100, Thomas Graf wrote: > On 10/29/14 at 11:46pm, Ben Pfaff wrote: > > A "conjunctive match" allows higher-level matches in the flow table, such > > as set membership matches, without causing a cross-product explosion for > > multidimensional matches. Please refer to the documentation that this > > commit adds to ovs-ofctl(8) for a better explanation, including an example. > > High level remark before I dig into the code: > > conjunction(id, k/n) > > I like n being the number of dimensions. I wonder whether we should > have k start at 1 instead of 0 though. It would read as 1/2 - "1st > dimension out of 2", 2/2 - "2nd dimension out of 2".
I'd be happy with that as the formatted syntax, but due to the use of bitmaps for the dimensions it would either cause extra +1/-1 in different places, or change the limit from 64 to 63 dimensions (which is probably still about 60 more than actually useful). I'll think about it for the next version. > > - Fixing reg0 as the field to use for conjunctive match lookup doesn't seem > > too great. We could make it configurable per-flow, or we could add a new > > field specifically for this purpose. I am not sure that it should be > > fixed to 32 bits, either. > > I guess we can't go wrong with a separate 64 bits field. We're starting to have a lot of fields. When struct flow exceeds 252 (63 * 4) bytes, we'll have to change how struct miniflow works because we can't make the 'map' member wider than 63 bits. Still, we do have some room. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
