[Cake] progress? dual-src/dsthost unfairness

[Jonathan Morton]

>> I tried Toke's and Jonathan's suggestion, dropping the
>> sparse_flow_count. Tthe results are the same (fairness).
>> In a hash collision in this patch the host_bulk_flow_count is not updated,
>> does this make sense?
> 
> Yeah, think so; it should be updated later when that flow transitions to
> bulk.
> 
> Care to resend with a proper commit message + signed-off-by line (or
> open a pull request on github)? I figure we can put it into the github
> repo for a bit more testing before submitting a patch upstream :)

The important thing is that the host_bulk_flow_count values match the actual bulk-status and host-reference properties assigned to each flow queue.  When a hash collision occurs, the bulk-status of the affected flow doesn't change but the hosts to which it refers might do.  In that case the host_bulk_flow_count values must be decremented on the old hosts and incremented on the new ones *if* the queue is in the bulk set.

 - Jonathan Morton