[LARTC] ESFQ not so fair?

[Patrick McHardy]

Andy Furniss wrote:
> Corey Hickey changed his esfq to use jhash for dst/src/fw - copy of his
> announce below.
> 
> Andy.
> 
> Corey Hickey wrote:
>> So, I wrote an alternative hash function. It's quite simple, and as long
>> as the range of input values is smaller than the hash table (default
> 1024,
>> up to 16384), collisions will not happen at all. See the updated README
>> file for more details.

Using jhash is a probably a good idea, the "improved" hash is broken
and will cause reordering in some circumstances:

return (h - q->dyn_min) * (q->hash_divisor - 1) / q->dyn_range;

dyn_min, dyn_max and dyn_range, as their name suggests, are adjusted
dynamically, so the hash function changes whenever one of these values
changes, resulting in reordering of packets belonging to a single flow.