> On 18 Sep 2015, at 6:17 pm, Stuart Henderson <[email protected]> wrote: > > On 2015-09-18, David Gwynne <[email protected]> wrote: >> this lets pf embed the state id into the mbuf as a "flow id" so >> other subsystems can use it. eg, trunk can pull it out and use it. > > I like this but it does change the path distribution. Previously all > flows from host A to host B were bound to a single path, now they are > spread across paths. This is good for making fuller use of paths but can > make fault diagnosis harder. > > I tried to work out the best way to make this optional when I sent my > earlier L4-hash diff (using PF states for this has similar results > and is far more elegant) but didn't settle on an approach. Switches > doing this usually have a single global setting (e.g. sysctl), which > seems a bit of a blunt instrument but would be easier to apply to areas > other than trunk (e.g. multipath routing). We could use an ioctl if > ifconfig(8) isn't full already, though I don't think we actually need > any more options than "L3-bound" and "per-flow" so using the existing > link0 scaffolding would be an easier way to do this per-trunk but > I didn't really get a feel for whether people thought that was > good enough.
the only "fault" ive experienced with hashing algorithms is that they all tend to make the wrong decision, so fixing it has been rotating through their different options till one sucks less than the others. is that what you're arguing for here? dlg
