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- 2022-09-02 krowe: sysctl -a | grep <10Gb NIC> between naasc-vs-3/naasc-vs-5 and are different
- naasc-vs-4 has entries for VLANs 101 and 140 while naasc-vs-3 and naasc-vs-5 have entries for VLANs 192 and 96.
- 2022-09-02 krowe: sysctl -a on naasc-vs-4 and naasc-vs-5 and found many questionable differences
- naasc-vs-4: net.iw_cm.default_backlog = 256
- Is this because the IB modules are loaded?
- naasc-vs-4: net.rdma_ucm.max_backlog = 1024
- Is this because the IB modules are loaded?
- naasc-vs-4: sunrpc.rdma*
- Is this because the IB modules are loaded?
- naasc-vs-4: net.netfilter.nf_log.2 = nfnetlink_log
- nfnetlink is a module for packet mangling. Could this interfear with the docker swarm networking?
- Though the recorded output rate of naasc-vs-5 is about 500 Mb/s while naasc-vs-{3..4} is about 300Kb/s.
- And the recorded input rate of naasc-vs-5 is about 500 Mb/s while naasc-vs{3..4} is about 5 Mb/s.
- This is very strange as it seemed naasc-vs-5 was the limiting factor but the switch ports suggest not. Perhaps this data rate is caused by other VM guests on naasc-vs-5 (helpdesk-prod, naascweb2-prod, cartaweb-prod, natest-arc-3, cobweb2-dev)
- naasc-vs-4: net.iw_cm.default_backlog = 256
- 2022-09-06 krowe: ethtool -k <NIC> for naasc-vs-3 and naasc-vs-4 are very different.
- hw-tc-offload: off vs hw-tc-offload: on
- rx-gro-hw: off vs rx-gro-hw: on
- rx-vlan-offload: off vs rx-vlan-offload: on
- rx-vlan-stag-hw-parse: off vs rx-vlan-stag-hw-parse: on
- tcp-segmentation-offload: off vs tcp-segmentation-offload: on
- tx-gre-csum-segmentation: off vs tx-gre-csum-segmentation: on
- tx-gre-segmentation: off vs tx-gre-segmentation: on
- tx-gso-partial: off vs x-gso-partial: on
- tx-ipip-segmentation: off vs tx-ipip-segmentation: on
- tx-sit-segmentation: off vs tx-sit-segmentation: on
- tx-tcp-segmentation: off vs tx-tcp-segmentation: on
- tx-udp_tnl-csum-segmentation: off vs tx-udp_tnl-csum-segmentation: on
- tx-udp_tnl-segmentation: off vs tx-udp_tnl-segmentation: on
- tx-vlan-offload: off vs tx-vlan-offload: on
- tx-vlan-stag-hw-insert: off vs tx-vlan-stag-hw-insert: on
- 2022-09-12 krowe: I found the rx and tx buffers for em1 on naasc-vs-4 were 511 while on naasc-vs-2, 3, and 5 were 1024. I changed naasc-vs-4 with the following ethtool -G em1 rx 1024 tx 1024 but it didn't change iperf performance.
- 2022-09-12 krowe: I found an article suggesting that gro can make traffic slower when it is enabled. I see that rx-gro-hw is enabled on naasc-vs-4 but disabled on naasc-vs-3 and 5. You can see this with ethtool -k em1 | grep gro.So I disabled it on naasc-vs-4 with ethtool -K em1 gro off and iperf3 tests now show about 2Gb/s both directions!!!
- GRO = Generic Receive Offload. It is hardware on the physical NIC. GRO is an aggregation technique to coalesce several receive packets from a stream into a single large packet, thus saving CPU cycles as fewer packets need to be processed by the kernel.
- https://bugzilla.redhat.com/show_bug.cgi?id=1424076
- After disabling rx-gro-hw, I no longer see TCP Retransmission or TCP Out-Of-Order packets when tracing the iperf3 test from na-arc-3 to na-arc-2.
na-arc-1,2,3,4,5
Identical
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