One question about TCP small queues (which I don't think is a good solution to the problem). For 802.11 to be able to perform well it needs to form maximum size aggregates. This means that it needs to maintain a minimum queue size of at least 64 packets, and sometimes more. Will TCP small queues prevent this? Simon Sent with AquaMail for Android http://www.aqua-mail.com On May 15, 2015 6:44:21 AM Jim Gettys wrote: > On Fri, May 15, 2015 at 9:09 AM, Bill Ver Steeg (versteb) > wrote: > > > Lars- > > > > You make some good points. It boils down to the fact that there are > > several things that you can measure, and they mean different things. > > > > Bvs > > > > > > -----Original Message----- > > From: Eggert, Lars [mailto:lars@netapp.com] > > Sent: Friday, May 15, 2015 8:44 AM > > To: Bill Ver Steeg (versteb) > > Cc: Aaron Wood; cake@lists.bufferbloat.net; Klatsky, Carl; > > cerowrt-devel@lists.bufferbloat.net; bloat > > Subject: Re: [Bloat] [Cerowrt-devel] heisenbug: dslreports 16 flow test vs > > cablemodems > > > > > > I disagree. You can use them to establish a lower bound on the delay an > > application over TCP will see, but not get an accurate estimate of that > > (because socket buffers are not included in the measurement.) And you rely > > on the network to not prioritize ICMP/UDP but otherwise leave it in the > > same queues. > > > > ​On recent versions of Linux and Mac, you can get most of the socket > buffers to "go away". I forget the socket option offhand.​ > > ​And TCP small queues in Linux means that Linux no longer gratuitously > generates packets just to dump them into the queue discipline system where > they will rot. > > How accurate this now can be is still an interesting question: but has > clearly improved the situation a lot over 3-4 years ago.​ > > > > > If you can instrument TCP in the kernel to make instantaneous RTT > > available to the application, that might work. I am not sure how you would > > roll that out in a timely manner, though. > > > > ​Well, the sooner one starts, the sooner it gets deployed.​ > > Jim > > > > ---------- > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat >