On Sun, Aug 5, 2012 at 10:35 AM, Eric Dumazet <[email protected]> wrote: > On Sun, 2012-08-05 at 19:26 +0200, Eric Dumazet wrote: > >> It could be a flaw in linux implementation, I admit we had so many bugs >> that it could very well be still buggy. > > And at first glance, the following tcpdump seems suspect : We can see > all ACK are delayed by about 40 ms but RFC 3168 (sec 6.1.3) does not mandate immediate ACKs for ECE marked ones? is this because ECN response is per round-trip?
> > 19:30:54.367739 IP (tos 0x3,CE, ttl 64, id 52620, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.], seq 156841:158289, > ack 1, win 115, options [nop,nop,TS val 3115533 ecr 111212487], length 1448 > 19:30:54.406063 IP (tos 0x0, ttl 64, id 62099, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.E], cksum 0xac88 > (incorrect -> 0xe2b7), ack 158289, win 551, options [nop,nop,TS val 111212491 > ecr 3115533], length 0 > > 19:30:54.407212 IP (tos 0x3,CE, ttl 64, id 52621, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [P.W], seq 158289:159737, > ack 1, win 115, options [nop,nop,TS val 3115573 ecr 111212491], length 1448 > 19:30:54.446057 IP (tos 0x0, ttl 64, id 62100, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.E], cksum 0xac88 > (incorrect -> 0xdce3), ack 159737, win 551, options [nop,nop,TS val 111212495 > ecr 3115573], length 0 > > > > 19:30:54.448209 IP (tos 0x3,CE, ttl 64, id 52622, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.W], seq 159737:161185, > ack 1, win 115, options [nop,nop,TS val 3115613 ecr 111212495], length 1448 > 19:30:54.486057 IP (tos 0x0, ttl 64, id 62101, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.E], cksum 0xac88 > (incorrect -> 0xd70f), ack 161185, win 551, options [nop,nop,TS val 111212499 > ecr 3115613], length 0 > > 19:30:54.487443 IP (tos 0x3,CE, ttl 64, id 52623, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.W], seq 161185:162633, > ack 1, win 115, options [nop,nop,TS val 3115653 ecr 111212499], length 1448 > 19:30:54.526069 IP (tos 0x0, ttl 64, id 62102, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.E], cksum 0xac88 > (incorrect -> 0xd13b), ack 162633, win 551, options [nop,nop,TS val 111212503 > ecr 3115653], length 0 > > 19:30:54.527241 IP (tos 0x2,ECT(0), ttl 64, id 52624, offset 0, flags [DF], > proto TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.W], seq 162633:164081, > ack 1, win 115, options [nop,nop,TS val 3115693 ecr 111212503], length 1448 > 19:30:54.566049 IP (tos 0x0, ttl 64, id 62103, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.], cksum 0xac88 > (incorrect -> 0xcba7), ack 164081, win 551, options [nop,nop,TS val 111212507 > ecr 3115693], length 0 > > 19:30:54.567809 IP (tos 0x3,CE, ttl 64, id 52625, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.], seq 164081:165529, > ack 1, win 115, options [nop,nop,TS val 3115733 ecr 111212507], length 1448 > 19:30:54.606067 IP (tos 0x0, ttl 64, id 62104, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.E], cksum 0xac88 > (incorrect -> 0xc593), ack 165529, win 551, options [nop,nop,TS val 111212511 > ecr 3115733], length 0 > 19:30:54.607088 IP (tos 0x2,ECT(0), ttl 64, id 52626, offset 0, flags [DF], > proto TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.W], seq 165529:166977, > ack 1, win 115, options [nop,nop,TS val 3115773 ecr 111212511], length 1448 > 19:30:54.646056 IP (tos 0x0, ttl 64, id 62105, offset 0, flags [DF], proto > TCP (6), length 52) > 172.30.42.18.50103 > 172.30.42.19.50341: Flags [.], cksum 0xac88 > (incorrect -> 0xbfff), ack 166977, win 551, options [nop,nop,TS val 111212515 > ecr 3115773], length 0 > 19:30:54.648105 IP (tos 0x3,CE, ttl 64, id 52627, offset 0, flags [DF], proto > TCP (6), length 1500) > 172.30.42.19.50341 > 172.30.42.18.50103: Flags [.], seq 166977:168425, > ack 1, win 115, options [nop,nop,TS val 3115813 ecr 111212515], length 1448 > > > > _______________________________________________ > Codel mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/codel _______________________________________________ Codel mailing list [email protected] https://lists.bufferbloat.net/listinfo/codel
