Alice Mikityanska 03ebe91b0f geneve: Enable BIG TCP packets
From: Daniel Borkmann <daniel@iogearbox.net>

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 geneve netdevs up to GSO_MAX_SIZE
to allow the admin to use BIG TCP with geneve tunnels.

BIG TCP on geneve 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    37391.34

  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    60.00    58030.19

BIG TCP on geneve 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    40891.57

  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    60.00    61458.39

Example receive side:

  swapper       0 [008]  3682.509996: net:netif_receive_skb: dev=geneve0 skbaddr=0xffff8f3b0a781800 len=129492
        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])
        ffffffff8cfe573c napi_complete_done+0x7c ([kernel.kallsyms])
        ffffffff8d046c23 gro_cell_poll+0x83 ([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 [002]  3403.688687: net:net_dev_xmit: dev=enp10s0f0np0 skbaddr=0xffff8af31d104ae8 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])
        ffffffffc179d3e0 geneve_xmit+0x920 ([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])
        ffffffffa76ca3b9 __tcp_push_pending_frames+0x39 ([kernel.kallsyms])
        ffffffffa76c1fb6 tcp_rcv_established+0x276 ([kernel.kallsyms])
        ffffffffa76d3957 tcp_v4_do_rcv+0x157 ([kernel.kallsyms])
        ffffffffa76d6053 tcp_v4_rcv+0x1243 ([kernel.kallsyms])
        ffffffffa769b8ea ip_protocol_deliver_rcu+0x2a ([kernel.kallsyms])
        ffffffffa769bab7 ip_local_deliver_finish+0x77 ([kernel.kallsyms])
        ffffffffa769bb4d ip_local_deliver+0x6d ([kernel.kallsyms])
        ffffffffa769abe7 ip_sublist_rcv_finish+0x37 ([kernel.kallsyms])
        ffffffffa769b713 ip_sublist_rcv+0x173 ([kernel.kallsyms])
        ffffffffa769bde2 ip_list_rcv+0x102 ([kernel.kallsyms])
        ffffffffa75e4868 __netif_receive_skb_list_core+0x178 ([kernel.kallsyms])
        ffffffffa75e4e52 netif_receive_skb_list_internal+0x1d2 ([kernel.kallsyms])
        ffffffffa75e573c napi_complete_done+0x7c ([kernel.kallsyms])
        ffffffffa7646c23 gro_cell_poll+0x83 ([kernel.kallsyms])
        ffffffffa75e586d __napi_poll+0x2d ([kernel.kallsyms])
        ffffffffa75e5f8d net_rx_action+0x20d ([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: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: Alice Mikityanska <alice@isovalent.com>
Signed-off-by: Alice Mikityanska <alice@isovalent.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260710134242.216538-9-alice.kernel@fastmail.im
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2026-07-22 13:47:02 +02:00
2026-07-22 13:47:02 +02:00
2026-01-26 19:07:09 -08:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-07-05 14:44:06 -10:00

Linux kernel
============

The Linux kernel is the core of any Linux operating system. It manages hardware,
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-----------

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-----------------------

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==================

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--------------------

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-------------------

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-----------------------------

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--------------------

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----------

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-----------------------

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