Luca Muscariello <luca.muscarie...@gmail.com> writes: > For highly asymmetric links, but also shared media like wifi, QUIC might be a > better playground for optimisations. > Not pervasive as TCP though and maybe off topic in this thread.
I happen to really like QUIC, but a netperf-style tool did not exist for it when I last looked, last year. Also getting to emulating DASH traffic is on my list. > > If the downlink is what one want to optimise, using FEC in the downstream, in > conjunction with flow control could be very effective. > No need to send ACK frequently and having something like FQ_codel in the > downstream would avoid fairness problems that might > happen though. I don't know if FEC is still in QUIC and used. > > BTW, for wifi, the ACK stream can be compressed in aggregate of frames and > sent > in bursts. This is similar to DOCSIS upstream. > I wonder if this is a phenomenon that is visible in recent WiFi or just > negligible. My guess is meraki deployed something and I think they are in in the top 5 in the enterprise market. I see ubnt added airtime fairness (of some sort), recently. > > On Fri, Dec 1, 2017 at 9:45 AM, Sebastian Moeller <moell...@gmx.de> wrote: > > Hi All, > > you do realize that the worst case is going to stay at 35KPPS? If we > assume > simply that the 100Mbps download rate is not created by a single flow but > by > many flows (say 70K flows) the discussed ACK frequency reduction schemes > will not work that well. So ACK thinning is a nice optimization, but will > not help the fact that some ISPs/link technologies simply are asymmetric > and > the user will suffer under some traffic conditions. Now the 70K flow > example > is too extreme, but the fact is at hight flow number with sparse flows (so > fewer ACKs per flow in the queue and fewer ACKs per flow reaching the end > NIC in a GRO-collection interval (I naively assume there is a somewhat > fixed > but small interval in which packets of the same flow are collected for > GRO)) > there will be problems. (Again, I am all for allowing the end user to > configure ACK filtering thinning, but I would rather see ISPs sell less > imbalanced links ;) ) > > Best Regards > Sebastian > > > > > On Dec 1, 2017, at 01:28, David Lang <da...@lang.hm> wrote: > > > > 35K PPS of acks is insane, one ack every ms is FAR more than enough to > do > 'fast recovery', and outside the datacenter, one ack per 10ms is probably > more than enough. > > > > Assuming something that's not too assymetric, thinning out the acks may > not make any difference in the transfer rate of a single data flow in one > direction, but if you step back and realize that there may be a need to > transfer data in the other direction, things change here. > > > > If you have a fully symmetrical link, and are maxing it out in both > direction, going from 35K PPs of aks competing with data packets and gonig > down to 1k PPS or 100 PPS (or 10 PPS) would result in a noticable > improvement in the flow that the acks are competing against. > > > > Stop thinking in terms of single-flow benchmarks and near idle > 'upstream' > paths. > > > > David Lang > > _______________________________________________ > > Bloat mailing list > > Bloat@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/bloat > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat > > > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat