On Thu, Mar 17, 2016 at 7:02 AM, Patrick Boutilier <bouti...@ednet.ns.ca> wrote: > I have an IPIP tunnel setup between two hosts in different buildings. The > Linux router they route through causes extreme slowness in the tunnel when > running kernels from 3.18 on . tcpdump shows many cksum errors which don't > show up in the 3.17 and earlier kernels. Speed goes back to normal when > rx-checksumming and tx-checksumming are turned off using ethtool on the > Linux router . Would this be an effect of bulk network packet transmission > that was introduced in 3.18 or some other issue? > If this is happening on a router then the only case where checksums are pertinent should be if GSO/GRO is enabled. Please try disabling these. Also, are these showing up as checksum errors on the receiver (netstat -s).
> > eth2 > driver: igb > version: 5.2.15-k > firmware-version: 1.5.1 > bus-info: 0000:06:00.0 > supports-statistics: yes > supports-test: yes > supports-eeprom-access: yes > supports-register-dump: yes > supports-priv-flags: no > > > eth6 > driver: ixgbe > version: 3.19.1-k > firmware-version: 0x80000389 > bus-info: 0000:41:00.0 > supports-statistics: yes > supports-test: yes > supports-eeprom-access: yes > supports-register-dump: yes > supports-priv-flags: no > > > > > > Example of cksum from tcpdump: > > Flags [.], cksum 0x2237 (incorrect -> 0xbb02), seq 424119200:424120648, ack > 1, win 115, options [nop,nop,TS val 303173784 ecr 3971495454], length 1448 > > > > > > Results of nuttcp test with rx-checksumming and tx-checksumming on: > > > Testing upload inside tunnel > > > > 0.0625 MB / 5.00 sec = 0.1048 Mbps 79 retrans > 0.0625 MB / 5.00 sec = 0.1048 Mbps 59 retrans > 0.0625 MB / 5.00 sec = 0.1049 Mbps 27 retrans > > 0.2096 MB / 16.11 sec = 0.1092 Mbps 0 %TX 0 %RX 186 retrans 0.47 > msRTT > > > > Testing download inside tunnel > > > > 0.5000 MB / 5.00 sec = 0.8389 Mbps 112 retrans > 2.6250 MB / 5.00 sec = 4.4040 Mbps 412 retrans > 0.8750 MB / 5.00 sec = 1.4680 Mbps 156 retrans > > 4.0243 MB / 15.48 sec = 2.1809 Mbps 0 %TX 0 %RX 705 retrans 0.47 > msRTT > > > Testing upload outside tunnel > > > > 423.0000 MB / 5.00 sec = 709.4949 Mbps 275 retrans > 442.0625 MB / 5.00 sec = 741.7008 Mbps 53 retrans > 418.5625 MB / 5.00 sec = 702.1329 Mbps 133 retrans > > 1287.0080 MB / 15.08 sec = 715.9252 Mbps 1 %TX 30 %RX 461 retrans 0.43 > msRTT > > > > Testing download outside tunnel > > > > 552.4375 MB / 5.00 sec = 926.8347 Mbps 26 retrans > 555.1875 MB / 5.00 sec = 931.4499 Mbps 17 retrans > 553.0000 MB / 5.00 sec = 927.7802 Mbps 16 retrans > > 1664.2149 MB / 15.03 sec = 928.6737 Mbps 9 %TX 5 %RX 60 retrans 0.46 > msRTT > > > > > > > Results of nuttcp test with rx-checksumming and tx-checksumming off: > > > > Testing upload inside tunnel > > > > 440.0000 MB / 5.00 sec = 738.0112 Mbps 117 retrans > 433.0000 MB / 5.00 sec = 726.4892 Mbps 135 retrans > 447.9375 MB / 5.00 sec = 751.5714 Mbps 112 retrans > > 1321.0069 MB / 15.04 sec = 736.7213 Mbps 3 %TX 21 %RX 364 retrans 0.51 > msRTT > > > > Testing download inside tunnel > > > > 494.0625 MB / 5.00 sec = 828.8973 Mbps 335 retrans > 471.0000 MB / 5.00 sec = 790.2050 Mbps 219 retrans > 469.8750 MB / 5.00 sec = 788.3174 Mbps 220 retrans > > 1435.1875 MB / 15.00 sec = 802.4203 Mbps 89 %TX 12 %RX 774 retrans 0.46 > msRTT > > > Testing upload outside tunnel > > > > 431.2500 MB / 5.00 sec = 723.2808 Mbps 33 retrans > 446.3750 MB / 5.00 sec = 748.9268 Mbps 10 retrans > 475.4375 MB / 5.00 sec = 797.7044 Mbps 0 retrans > > 1355.0834 MB / 15.06 sec = 754.6438 Mbps 1 %TX 33 %RX 43 retrans 0.53 > msRTT > > > > Testing download outside tunnel > > > > 424.8125 MB / 5.00 sec = 712.7061 Mbps 102 retrans > 456.5625 MB / 5.00 sec = 765.9872 Mbps 80 retrans > 454.0000 MB / 5.00 sec = 761.6935 Mbps 116 retrans > > 1335.7823 MB / 15.01 sec = 746.6959 Mbps 4 %TX 5 %RX 298 retrans 0.55 > msRTT
