[v2,net-next,00/14] tcp: BIG TCP implementation

Message

Eric Dumazet March 3, 2022, 6:15 p.m. UTC

From: Eric Dumazet <[e-mail]>

This series implements BIG TCP as presented in netdev 0x15:

https://netdevconf.info/0x15/session.html?BIG-TCP

Jonathan Corbet made a nice summary: https://lwn.net/Articles/884104/

Standard TSO/GRO packet limit is 64KB

With BIG TCP, we allow bigger TSO/GRO packet sizes for IPv6 traffic.

Note that this feature is by default not enabled, because it might
break some eBPF programs assuming TCP header immediately follows IPv6 header.

Reducing number of packets traversing networking stack usually improves
performance, as shown on this experiment using a 100Gbit NIC, and 4K MTU.

'Standard' performance with current (74KB) limits.
for i in {1..10}; do ./netperf -t TCP_RR -H iroa23  -- -r80000,80000 -O MIN_LATENCY,P90_LATENCY,P99_LATENCY,THROUGHPUT|tail -1; done
77           138          183          8542.19    
79           143          178          8215.28    
70           117          164          9543.39    
80           144          176          8183.71    
78           126          155          9108.47    
80           146          184          8115.19    
71           113          165          9510.96    
74           113          164          9518.74    
79           137          178          8575.04    
73           111          171          9561.73    

Now enable BIG TCP on both hosts.

ip link set dev eth0 gro_ipv6_max_size 185000 gso_ipv6_max_size 185000
for i in {1..10}; do ./netperf -t TCP_RR -H iroa23  -- -r80000,80000 -O MIN_LATENCY,P90_LATENCY,P99_LATENCY,THROUGHPUT|tail -1; done
57           83           117          13871.38   
64           118          155          11432.94   
65           116          148          11507.62   
60           105          136          12645.15   
60           103          135          12760.34   
60           102          134          12832.64   
62           109          132          10877.68   
58           82           115          14052.93   
57           83           124          14212.58   
57           82           119          14196.01   

We see an increase of transactions per second, and lower latencies as well.

v2: Removed the MAX_SKB_FRAGS change, this belongs to a different series.
    Addressed feedback, for Alexander and nvidia folks.

Coco Li (5):
  ipv6: add dev->gso_ipv6_max_size
  ipv6: add GRO_IPV6_MAX_SIZE
  ipv6: Add hop-by-hop header to jumbograms in ip6_output
  ipvlan: enable BIG TCP Packets
  mlx5: support BIG TCP packets

Eric Dumazet (9):
  net: add netdev->tso_ipv6_max_size attribute
  tcp_cubic: make hystart_ack_delay() aware of BIG TCP
  ipv6: add struct hop_jumbo_hdr definition
  ipv6/gso: remove temporary HBH/jumbo header
  ipv6/gro: insert temporary HBH/jumbo header
  net: loopback: enable BIG TCP packets
  bonding: update dev->tso_ipv6_max_size
  macvlan: enable BIG TCP Packets
  mlx4: support BIG TCP packets

 drivers/net/bonding/bond_main.c               |  3 +
 .../net/ethernet/mellanox/mlx4/en_netdev.c    |  3 +
 drivers/net/ethernet/mellanox/mlx4/en_tx.c    | 47 +++++++++--
 .../net/ethernet/mellanox/mlx5/core/en_main.c |  1 +
 .../net/ethernet/mellanox/mlx5/core/en_tx.c   | 82 +++++++++++++++----
 drivers/net/ipvlan/ipvlan_main.c              |  1 +
 drivers/net/loopback.c                        |  2 +
 drivers/net/macvlan.c                         |  1 +
 include/linux/ipv6.h                          |  1 +
 include/linux/netdevice.h                     | 32 ++++++++
 include/net/ipv6.h                            | 44 ++++++++++
 include/uapi/linux/if_link.h                  |  3 +
 net/core/dev.c                                |  4 +
 net/core/gro.c                                | 20 ++++-
 net/core/rtnetlink.c                          | 33 ++++++++
 net/core/sock.c                               |  6 ++
 net/ipv4/tcp_cubic.c                          |  4 +-
 net/ipv6/ip6_offload.c                        | 56 ++++++++++++-
 net/ipv6/ip6_output.c                         | 22 ++++-
 tools/include/uapi/linux/if_link.h            |  3 +
 20 files changed, 334 insertions(+), 34 deletions(-)