On Tue, 2015-07-28 at 16:49 +0200, Eric Dumazet wrote: > On Tue, 2015-07-28 at 07:31 -0700, Simon Barber wrote: > > The issue is that Codel tries to keep the delay low, and will start > > dropping when sojourn time grows above 5ms for 100ms. For longer RTT links > > more delay is necessary to avoid underutilizing the link. This is due to > > the multiplicative decrease - it's worst with Reno, where the halving of > > cWind means that you need to have a full BDP of data in the buffer to avoid > > the link going idle when cWind is halved. With longer RTTs this means more > > delay than Codel allows is required to avoid a throughput hit. The worst > > case happens when a single flow is controlled, but that can be a common > > situation. My proposal is to sense and have the target value in Codel > > automatically adjust when this worst case scenario happens - which would > > mitigate most of the downside. > > As I said, I've never seen what you describe. > > 100ms value is not a go/nogo threshold. It is a hint, based on real > world values. We are speaking of 100 ms sojourn time in the CoDel queue,
typo : 5 ms ( codel target ) _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
