On 21/02/19(Thu) 14:19, David Gwynne wrote: > right now we add vlan_input as a possible input handler on the parent > interface, and if the packet is for a vlan we take it and pretend we > received it on the vlan interface by calling if_input against that mbuf. > > as mpi notes, the if input queue stuff looks like a lot of work, > especially for a single packet. my opinion is that we got away with > the if input stuff we've done to try and encourage an mpsafe network > stack because we amortised the cost of it over many packets off the > hardware ring. vlan does it a packet at a time. > > this moves the handling of vlan packets back into ether_input by > calling vlan_input directly on packets that are either marked as vlan > tagged or have a vlan ethertype. note that we have to do that anyway, > this just makes it explicit. > > vlan_input is then tweaked to implement all the important bits of if > input. part of what if input does is count the packets. because vlan > already has per cpu counters for bypassing queues on output, we can use > them again for input from any cpu. if i ever get round to making a > driver handle multiple rx rings this means we can rx vlan packets > concurrently, they don't get serialised to a single if input q. > > finally, hrvoje popovski has tested this diff and get's a significant > bump with it. on a machine that can forward 1100Kpps without vlan, it > goes from 790Kpps with vlan to 870Kpps. On a box that can do 730Kpps > without vlans, it goes from 550Kpps with vlan to 840Kpps. We're > still trying to figure that last one out, but it does appear to be > faster. > > thoughts? ok?
Why do we need to move stuff to ether_input() if all we want is to bypass ifiq_input()? Isn't a 3 line diff enough^^ ? - ml_enqueue(&ml, m); - if_input(&ifv->ifv_if, &ml); + if_input_one(&ifv->ifv_if, m); I'm saying that because I'm afraid of the breakage that will happen if we remove the input handlers. So I'm not opposed to get rid of the handlers, but as you said we should consider all drivers to not break trunk on top of bridge on top of vlan or whatever crazy configuration people do. Another point to keep in mind if you're going to remove the handlers is: do we want to keep passing a single mbuf or was it a plan to pass the whole list?
