Fabian Ruffy <[email protected]> writes: > Hello, > > this is a somewhat esoteric question. I am trying to actually force > bufferbloat > in an emulation setup I am using. I set up a dumbbell topology and push > traffic > through it, causing congestion at the central link. I use this setup to > compare > congestion avoidance algorithms such as DCTCP to other solutions. > This has worked nicely with the 4.18 kernel. However, after upgrading to 4.19 > I > cannot reproduce bufferbloat anymore. The traffic (even UDP packets) is > perfectly rate limited and I never see any congestion happening. This is > great, > but in practice it prevents me from prototyping algorithms.
Ha, that's awesome! :D > My interface configuration for bottlenecked links is: > > qdisc tbf 5: dev OBcbnsw1-eth2 root refcnt 2 rate 10Mbit burst 15000b lat > 12.0ms > Sent 6042 bytes 51 pkt (dropped 0, overlimits 0 requeues 0) > backlog 0b 0p requeues 0 > qdisc netem 10: dev OBcbnsw1-eth2 parent 5:1 limit 500 > Sent 6042 bytes 51 pkt (dropped 0, overlimits 0 requeues 0) > backlog 0b 0p requeues 0 > > > I have the suspicion that it is related to the CAKE changes in the 4.19 > kernel, > but I am not exactly sure. I am not using tc cake at all. Do you maybe know > what could cause this behavior? Apologies if this is the wrong mailing > list. My guess would be changes in the TCP stack; can't point you to anything specific off the top of my head, though... -Toke _______________________________________________ Cake mailing list [email protected] https://lists.bufferbloat.net/listinfo/cake
