On Sat, Jan 12, 2019 at 07:12:34AM -0500, Jamal Hadi Salim wrote: > On 2019-01-10 8:45 a.m., Simon Horman wrote: > > On Sun, Jan 06, 2019 at 09:44:30AM -0500, Jamal Hadi Salim wrote: > > > > You can use flower instead of basic but such one offs basic would > > > be more effective. > > > Bartek, if you say you have 20 vlans: worst case scenario > > > here is you are going to do 20 lookups (with basic) before > > > hitting the efficient u32 lookup alg and of course best case > > > is 1 lookup. > > > > FWIW, flower's lookup is hash-based so I would expect it to do better > > than O(n). > > > > Referring more to a large number of filters(N) in particular: > Flower will perform at O(N) to find a match (not sure > you can make it perform better than O(N)) but u32 > can made to perform at _much better_ than O(logN); > i havent looked closely at Bartek's arrangement but cursory inspection > indicates he is using such an arrangement for performance.
For all filters are at the same priority with the same mask Flower will use a hash lookup which I expect that would be better than O(N). That was the only point I wanted to make. > > > > We can add vlan as a metadata extension to u32 - just > > > like skb->mark is. It will help to remove the need for basic > > > filter but may be pushing it > > > > That sounds more like fixing a long standing regression than a new feature > > to me. I'm not sure that I understand what it would be pushing. > > > > It will be a new feature in the sense the user will have to specify > something like (adding "mark" for clarify): > > tc filter add .... protocol 802.1q .. u32 \ > match u32 0 0 \ > mark 15 \ > vlanid 1234 > action vlan pop reclassify > > As opposed to what used to work before which would > have matched at packet offset. So the old feature is permanently broken? > If there is agreement (lots of bikeshedding last time) > i or someone else can whip a patch for this. Backwards compatibility aside I have no objection.
