Am 28.01.25 um 00:32 schrieb David Gwynne:
>>>> Doesn't does gratuitously reorder forwarded packets?
>>>
>>> it does allow packets in "conversations" to be reordered, yes.
>>>
>>> there's no guarantee that packets within a conversation are always
>>> processed on a specific cpu, which is what allows packets to be
>>> reordered. this is true for both softnet threads when forwarding,
>>> and userland programs producing packets.
>>>
>>> fwiw, flowids are not defined to be a toeplitz hash, they're best
>>> effort set to something that hopes to spread packets out over things
>>> like softnet threads, ports in lacp aggregations, and tx queues on
>>> network cards. we try and make things that can do teoplitz use toeplitz,
>>> but if that's not available then whatever is handy is still better than
>>> nothing.
>>>
>>> in this situation id have vio set the flowid to the rx queue id.
>>
>> The diff below does that. Do we expect any disadvantage if we set this
>> simplistic flowid and pf will then not set the "properly" calculated one?
> 
> i do basically the same thing in other places and it's fine. your diff
> below is ok by me. if we make something better you can change it.

committed, thanks.

> 
>> Each of the diff below and Chris Cappuccio's ifq_pkt_hash() diff speed up
>> udp forwarding without pf to 2-3 times single queue performance. But the
>> variation is rather high, so I cannot determine if one diff is better. For
>> udp with pf and for tcp forwarding, I cannot see a difference either.
> 
> what do you mean by "the variation is rather high" and "I cannot
> see a difference"?

Benchmark results vary quite a bit from run to run, maybe by 20%. So any 
smaller difference is lost in the noise.