From: Maxim Mikityanskiy From: Maxim Mikityanskiy In Cilium we do support BIG TCP, but so far the latter has only been enabled for direct routing use-cases. A lot of users rely on Cilium with vxlan/geneve tunneling though. The underlying kernel infra for tunneling has not been supporting BIG TCP up to this point. Given we do now, bump tso_max_size for vxlan netdevs up to GSO_MAX_SIZE to allow the admin to use BIG TCP with vxlan tunnels. BIG TCP on vxlan disabled: Standard MTU: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 30.00 34440.00 8k MTU: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 262144 32768 32768 30.00 55684.26 BIG TCP on vxlan enabled: Standard MTU: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 30.00 39564.78 8k MTU: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 262144 32768 32768 30.00 61466.47 When tunnel offloads are not enabled/exposed and we fully need to rely on SW-based segmentation on transmit (e.g. in case of Azure) then the more aggressive batching also has a visible effect. Below example was on the same setup as with above benchmarks but with HW support disabled: # ethtool -k enp10s0f0np0 | grep udp tx-udp_tnl-segmentation: off tx-udp_tnl-csum-segmentation: off tx-udp-segmentation: off rx-udp_tunnel-port-offload: off rx-udp-gro-forwarding: off Before: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 60.00 21820.82 After: # netperf -H 10.1.0.2 -t TCP_STREAM -l60 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.1.0.2 () port 0 AF_INET : demo Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 131072 16384 16384 60.00 29390.78 Example receive side: swapper 0 [002] 4712.645070: net:netif_receive_skb: dev=enp10s0f0np0 skbaddr=0xffff8f3b086e0200 len=129542 ffffffff8cfe3aaa __netif_receive_skb_core.constprop.0+0x6ca ([kernel.kallsyms]) ffffffff8cfe3aaa __netif_receive_skb_core.constprop.0+0x6ca ([kernel.kallsyms]) ffffffff8cfe47dd __netif_receive_skb_list_core+0xed ([kernel.kallsyms]) ffffffff8cfe4e52 netif_receive_skb_list_internal+0x1d2 ([kernel.kallsyms]) ffffffff8d0210d8 gro_complete.constprop.0+0x108 ([kernel.kallsyms]) ffffffff8d021724 dev_gro_receive+0x4e4 ([kernel.kallsyms]) ffffffff8d021a99 gro_receive_skb+0x89 ([kernel.kallsyms]) ffffffffc06edb71 mlx5e_handle_rx_cqe_mpwrq+0x131 ([kernel.kallsyms]) ffffffffc06ee38a mlx5e_poll_rx_cq+0x9a ([kernel.kallsyms]) ffffffffc06ef2c7 mlx5e_napi_poll+0x107 ([kernel.kallsyms]) ffffffff8cfe586d __napi_poll+0x2d ([kernel.kallsyms]) ffffffff8cfe5f8d net_rx_action+0x20d ([kernel.kallsyms]) ffffffff8c35d252 handle_softirqs+0xe2 ([kernel.kallsyms]) ffffffff8c35d556 __irq_exit_rcu+0xd6 ([kernel.kallsyms]) ffffffff8c35d81e irq_exit_rcu+0xe ([kernel.kallsyms]) ffffffff8d2602b8 common_interrupt+0x98 ([kernel.kallsyms]) ffffffff8c000da7 asm_common_interrupt+0x27 ([kernel.kallsyms]) ffffffff8d2645c5 cpuidle_enter_state+0xd5 ([kernel.kallsyms]) ffffffff8cf6358e cpuidle_enter+0x2e ([kernel.kallsyms]) ffffffff8c3ba932 call_cpuidle+0x22 ([kernel.kallsyms]) ffffffff8c3bfb5e do_idle+0x1ce ([kernel.kallsyms]) ffffffff8c3bfd79 cpu_startup_entry+0x29 ([kernel.kallsyms]) ffffffff8c30a6c2 start_secondary+0x112 ([kernel.kallsyms]) ffffffff8c2c142d common_startup_64+0x13e ([kernel.kallsyms]) Example transmit side: swapper 0 [005] 4768.021375: net:net_dev_xmit: dev=enp10s0f0np0 skbaddr=0xffff8af32ebe1200 len=129556 rc=0 ffffffffa75e19c3 dev_hard_start_xmit+0x173 ([kernel.kallsyms]) ffffffffa75e19c3 dev_hard_start_xmit+0x173 ([kernel.kallsyms]) ffffffffa7653823 sch_direct_xmit+0x143 ([kernel.kallsyms]) ffffffffa75e2780 __dev_queue_xmit+0xc70 ([kernel.kallsyms]) ffffffffa76a1205 ip_finish_output2+0x265 ([kernel.kallsyms]) ffffffffa76a1577 __ip_finish_output+0x87 ([kernel.kallsyms]) ffffffffa76a165b ip_finish_output+0x2b ([kernel.kallsyms]) ffffffffa76a179e ip_output+0x5e ([kernel.kallsyms]) ffffffffa76a19d5 ip_local_out+0x35 ([kernel.kallsyms]) ffffffffa770d0e5 iptunnel_xmit+0x185 ([kernel.kallsyms]) ffffffffc179634e nf_nat_used_tuple_new.cold+0x1129 ([kernel.kallsyms]) ffffffffc17a7301 vxlan_xmit_one+0xc21 ([kernel.kallsyms]) ffffffffc17a80a2 vxlan_xmit+0x4a2 ([kernel.kallsyms]) ffffffffa75e18af dev_hard_start_xmit+0x5f ([kernel.kallsyms]) ffffffffa75e1d3f __dev_queue_xmit+0x22f ([kernel.kallsyms]) ffffffffa76a1205 ip_finish_output2+0x265 ([kernel.kallsyms]) ffffffffa76a1577 __ip_finish_output+0x87 ([kernel.kallsyms]) ffffffffa76a165b ip_finish_output+0x2b ([kernel.kallsyms]) ffffffffa76a179e ip_output+0x5e ([kernel.kallsyms]) ffffffffa76a1de2 __ip_queue_xmit+0x1b2 ([kernel.kallsyms]) ffffffffa76a2135 ip_queue_xmit+0x15 ([kernel.kallsyms]) ffffffffa76c70a2 __tcp_transmit_skb+0x522 ([kernel.kallsyms]) ffffffffa76c931a tcp_write_xmit+0x65a ([kernel.kallsyms]) ffffffffa76cb42e tcp_tsq_write+0x5e ([kernel.kallsyms]) ffffffffa76cb7ef tcp_tasklet_func+0x10f ([kernel.kallsyms]) ffffffffa695d9f7 tasklet_action_common+0x107 ([kernel.kallsyms]) ffffffffa695db99 tasklet_action+0x29 ([kernel.kallsyms]) ffffffffa695d252 handle_softirqs+0xe2 ([kernel.kallsyms]) ffffffffa695d556 __irq_exit_rcu+0xd6 ([kernel.kallsyms]) ffffffffa695d81e irq_exit_rcu+0xe ([kernel.kallsyms]) ffffffffa78602b8 common_interrupt+0x98 ([kernel.kallsyms]) ffffffffa6600da7 asm_common_interrupt+0x27 ([kernel.kallsyms]) ffffffffa78645c5 cpuidle_enter_state+0xd5 ([kernel.kallsyms]) ffffffffa756358e cpuidle_enter+0x2e ([kernel.kallsyms]) ffffffffa69ba932 call_cpuidle+0x22 ([kernel.kallsyms]) ffffffffa69bfb5e do_idle+0x1ce ([kernel.kallsyms]) ffffffffa69bfd79 cpu_startup_entry+0x29 ([kernel.kallsyms]) ffffffffa690a6c2 start_secondary+0x112 ([kernel.kallsyms]) ffffffffa68c142d common_startup_64+0x13e ([kernel.kallsyms]) Signed-off-by: Maxim Mikityanskiy Co-developed-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Cc: Nikolay Aleksandrov --- drivers/net/vxlan/vxlan_core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c index a5c55e7e4d79..a443adde8848 100644 --- a/drivers/net/vxlan/vxlan_core.c +++ b/drivers/net/vxlan/vxlan_core.c @@ -3341,6 +3341,8 @@ static void vxlan_setup(struct net_device *dev) dev->hw_features |= NETIF_F_RXCSUM; dev->hw_features |= NETIF_F_GSO_SOFTWARE; netif_keep_dst(dev); + netif_set_tso_max_size(dev, GSO_MAX_SIZE); + dev->priv_flags |= IFF_NO_QUEUE; dev->change_proto_down = true; dev->lltx = true; -- 2.50.1