Hi Andy,
> On Feb 27, 2017, at 19:02, Andy Furniss <[email protected]> wrote: > > Sebastian Moeller wrote: >> Looking at tc-adv, I would recommend to use “rtt 50” (maybe it is >> “rtt 50ms”) which allows to directly explicitly request a new >> “interval” (which IIRC is corresponding to the time you allow for >> the TCP control loop to react to cake’s ecn-marking/dropping) >> “target’ will be calculated as 5% of the explicit interval, in >> accordance with the rationale in the codel RFC. > > 50 is certainly better than 10, but still seems to hurt single a bit > even on a close server. Oopps, what I meant to convey is that there is the numeric option “rtt NNN” that allows to select the exact RTT/interval you believe to be valid. I picked 50 just because I wanted to give a concrete example, not because I believe 50 to be correct for your experiments... > > On more distant servers maybe even more - I am getting results that are > too variable to tell properly at the current time (of day). > > http://www.thinkbroadband.com/speedtest/results.html?id=1488216166262542155 > > Almost OK, but with 100ms this test usually shows x1 and x6 the same. > > http://www.thinkbroadband.com/speedtest/results.html?id=1488218291872647755 Interesting. My mental image is that interval defines the time you give both involved TCPs to get their act together before escalating cake’s/codel’s signaling. The theory as far as I understand it says that the RTT is the lower bound for the time required, so I am not totally amazed that relaxing that interval a bit increases bandwidth utilisation at a vert moderate latency cost (if any). The art is to figure out how to pick the interval (and I believe the codel paper showed, that at least for codel the exact number is not so important but the ballpark/ order of magnitude should match). > > Of course as we all know ingress shaping is a different beast anyway and > would deserve its own thread. The cool thing is that ingress shaping with all its “approximateness” (is that a word) works as well as it does ;) Best Regards _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
