On 03/17/2016 01:47 PM, Tom Herbert wrote:
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).
Yes, turning off GSO/GRO also fixes the issue. Not sure which value of netstat I am looking for.Compiling a new kernel now with Jesse's patch to test. Will report back in a bit.
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
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