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[v6,net-next,00/13] tcp: BIG TCP implementation

Message ID 20220510033219.2639364-1-eric.dumazet@gmail.com (mailing list archive)
Headers show
Series tcp: BIG TCP implementation | expand

Message

Eric Dumazet May 10, 2022, 3:32 a.m. UTC
From: Eric Dumazet <edumazet@google.com>

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.

While tcpdump recognizes the HBH/Jumbo header, standard pcap filters
are unable to skip over IPv6 extension headers.

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_max_size 185000 gso_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.

v6: fix a compilation error for CONFIG_IPV6=n in
    "net: allow gso_max_size to exceed 65536", reported by kernel bots.

v5: Replaced two patches (that were adding new attributes) with patches
    from Alexander Duyck. Idea is to reuse existing gso_max_size/gro_max_size

v4: Rebased on top of Jakub series (Merge branch 'tso-gso-limit-split')
    max_tso_size is now family independent.

v3: Fixed a typo in RFC number (Alexander)
    Added Reviewed-by: tags from Tariq on mlx4/mlx5 parts.

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


Alexander Duyck (2):
  net: allow gso_max_size to exceed 65536
  net: allow gro_max_size to exceed 65536

Coco Li (2):
  ipv6: Add hop-by-hop header to jumbograms in ip6_output
  mlx5: support BIG TCP packets

Eric Dumazet (9):
  net: add IFLA_TSO_{MAX_SIZE|SEGS} attributes
  net: limit GSO_MAX_SIZE to 524280 bytes
  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
  veth: enable BIG TCP packets
  mlx4: support BIG TCP packets

 drivers/net/ethernet/amd/xgbe/xgbe.h          |  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_rx.c   |  2 +-
 .../net/ethernet/mellanox/mlx5/core/en_tx.c   | 84 +++++++++++++++----
 drivers/net/ethernet/sfc/ef100_nic.c          |  3 +-
 drivers/net/ethernet/sfc/falcon/tx.c          |  3 +-
 drivers/net/ethernet/sfc/tx_common.c          |  3 +-
 drivers/net/ethernet/synopsys/dwc-xlgmac.h    |  3 +-
 drivers/net/hyperv/rndis_filter.c             |  2 +-
 drivers/net/loopback.c                        |  2 +
 drivers/net/veth.c                            |  1 +
 drivers/scsi/fcoe/fcoe.c                      |  2 +-
 include/linux/ipv6.h                          |  1 +
 include/linux/netdevice.h                     | 15 +++-
 include/net/ipv6.h                            | 44 ++++++++++
 include/uapi/linux/if_link.h                  |  2 +
 net/bpf/test_run.c                            |  2 +-
 net/core/dev.c                                |  9 +-
 net/core/gro.c                                |  8 ++
 net/core/rtnetlink.c                          | 16 ++--
 net/core/sock.c                               | 14 ++++
 net/ipv4/tcp_bbr.c                            |  2 +-
 net/ipv4/tcp_cubic.c                          |  4 +-
 net/ipv4/tcp_output.c                         |  2 +-
 net/ipv6/ip6_offload.c                        | 56 ++++++++++++-
 net/ipv6/ip6_output.c                         | 22 ++++-
 net/sctp/output.c                             |  3 +-
 tools/include/uapi/linux/if_link.h            |  2 +
 30 files changed, 301 insertions(+), 60 deletions(-)

Comments

Alexander Duyck May 10, 2022, 7:49 p.m. UTC | #1
On Mon, 2022-05-09 at 20:32 -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> 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.
> 
> While tcpdump recognizes the HBH/Jumbo header, standard pcap filters
> are unable to skip over IPv6 extension headers.
> 
> 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_max_size 185000 gso_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.
> 
> v6: fix a compilation error for CONFIG_IPV6=n in
>     "net: allow gso_max_size to exceed 65536", reported by kernel bots.
> 
> v5: Replaced two patches (that were adding new attributes) with patches
>     from Alexander Duyck. Idea is to reuse existing gso_max_size/gro_max_size
> 
> v4: Rebased on top of Jakub series (Merge branch 'tso-gso-limit-split')
>     max_tso_size is now family independent.
> 
> v3: Fixed a typo in RFC number (Alexander)
>     Added Reviewed-by: tags from Tariq on mlx4/mlx5 parts.
> 
> v2: Removed the MAX_SKB_FRAGS change, this belongs to a different series.
>     Addressed feedback, for Alexander and nvidia folks.
> 
> 
> Alexander Duyck (2):
>   net: allow gso_max_size to exceed 65536
>   net: allow gro_max_size to exceed 65536
> 
> Coco Li (2):
>   ipv6: Add hop-by-hop header to jumbograms in ip6_output
>   mlx5: support BIG TCP packets
> 
> Eric Dumazet (9):
>   net: add IFLA_TSO_{MAX_SIZE|SEGS} attributes
>   net: limit GSO_MAX_SIZE to 524280 bytes
>   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
>   veth: enable BIG TCP packets
>   mlx4: support BIG TCP packets

Looked over the changes to my patches and they all look good (sorry for
not catching that myself). This approach addresses all the concerns I
had.

For the series:
Acked-by: Alexander Duyck <alexanderduyck@fb.com>