On Sun, 2012-08-05 at 18:54 +0200, Richard Scheffenegger wrote: > Hi Eric, > > ----- Original Message ----- > From: "Eric Dumazet" <[email protected]> > To: "Andrew McGregor" <[email protected]> > Cc: <[email protected]> > Sent: Sunday, August 05, 2012 7:30 AM > Subject: Re: [Codel] [RFC PATCH] codel: ecn mark at target > > > > On Sat, 2012-08-04 at 20:06 -0700, Andrew McGregor wrote: > >> Well, thanks Eric for trying it. > >> > >> Hmm. How was I that wrong? Because I was supporting that idea. > >> > >> Time to think. > > > > No problem Andrew ;) > > > > Its seems ECN is not well enough understood. > > > > ECN marking a packet has the same effect for the sender : reducing cwnd > > exactly like a packet drop. Only difference is avoiding the > > retransmit[s]. > > That's true for the first mark; any subsequent mark (during the same window) > should have no effect - thus a high marking rate (marking fraction per > window) should not be that much worse... Of course, the queue can never know > the effective window of the tcp stream it is marking... >
Once your cwnd is 1 packet, and RTT is 100ms, what can you get from this, if all your packets have ECN mark ? > As a test, when the marking is done really instead of drop, do you see > fairness betwenn the ecn and legacy tcp flows? (if not, the ecn > implementation may be faulty). Yes its fine as mentioned in my test : codel , and I get 50/50 split between my two flows. It could be a flaw in linux implementation, I admit we had so many bugs that it could very well be still buggy. _______________________________________________ Codel mailing list [email protected] https://lists.bufferbloat.net/listinfo/codel
