> On Nov 24, 2017, at 12:21, Toke Høiland-Jørgensen <[email protected]> wrote: > > Dave Taht <[email protected]> writes: > >> Pete Heist <[email protected]> writes: >> >>> On Nov 23, 2017, at 10:44 AM, Jonathan Morton <[email protected]> >>> wrote: >>> >>> This is most likely an interaction of the AQM with Linux' scheduling >>> latency. >>> >>> At the 'lan' setting, the time comstants are similar in magnitude to the >>> delays induced by Linux itself, so congestion might be signalled >>> prematurely. The flows will then become sparse and total throughput >>> reduced, >>> leaving little or no back-pressure for the fairness logic to work >>> against. >> >> Agreed. >> >> man page add: >> >> At the 'lan' setting(1ms), the time constants are similar in magnitude >> to the jitter in the Linux kernel itself, so congestion might be >> signalled prematurely. The flows will then become sparse and total >> throughput reduced, leaving little or no back-pressure for the fairness >> logic to work against. Use the "metro" setting for local lans unless you >> have a custom kernel. > > Erm, doesn't this make the 'lan' keyword pretty much useless? So why not > just remove it? Or redefine it to something that actually works? 3ms?
The same applies for datacentre (0.1 ms), no? But I agree, let's not expose these as explicit keywords, one can always use "rtt [100us|1ms]" I assume... > > -Toke > > _______________________________________________ > Cake mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/cake _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
