> On 3 Mar, 2019, at 1:26 pm, Sebastian Moeller <[email protected]> wrote: > >>> Doesn't this look like ingress magic being applied selectively to the users >>> based on number of flows? I thought that the idea behind the ingress >>> keyword is to effectively shape harder the more bulk flows are coming in. >> >> No, it simply counts dropped packets against the shaper, as well as those >> actually transmitted. > > Sure, but the question is how is the resulting "pressure" to drop/mark > distributed over the existing (bulk) flows. > >> There shouldn't be that many packets being dropped to make this much of a >> difference. > > My intuition (probably wrong) is that is not the few packets dropped, but the > fact that the the dropping does seem to be restricted to the flows of the IP > with more flows, no?
As long as there is a backoff response to a dropped packet, the extra back-pressure should be contained to the flows experiencing drops, and other flows should see no difference - so you should see a slight reduction in goodput on the 16 flows, but *no increase* on the single flow in parallel. Even if that were not the case, the single flow should take longer on average to recover from a cwnd reduction (even in CUBIC) to the fair BDP. That should result in a greater reduction in goodput on the single flow than the many flows - but we see the reverse here. So I'm not entirely sure what's happening here, but at least the asymmetry isn't too bad; it's achieving significantly better host-fairness than a pure flow-fair system would. - Jonathan Morton _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
