[PATCH v2 net-next 0/7] Stacked vlan TSO

[Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>]

On the basis of Netdev 0.1 discussion[1], I made a patch set to enable
TSO for packets with multiple vlans.

Currently, packets with multiple vlans are always segmented by software,
which is caused by that netif_skb_features() drops most feature flags
for multiple tagged packets.

To allow NICs to segment them, we need to get rid of that check from core.
Fortunately, recently introduced ndo_features_check() can be used to
move the check to each driver, and this patch set is based on the idea.

For the initial patch set, I chose 3 drivers, bonding, team, and igb, as
candidates to enable TSO. I tested them and confirmed they works fine
with this change.

Here are samples of performance test results. As I expected, %sys gets
pretty lower than before.

* TEST1: vlan (.1Q) on vlan (.1ad) on igb (I350)

- before

$ netperf -t TCP_STREAM -H 192.168.10.1 -l 60
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    60.02     933.72

Average:        CPU     %user     %nice   %system   %iowait    %steal     %idle
Average:        all      0.13      0.00     11.28      0.01      0.00     88.58

- after

$ netperf -t TCP_STREAM -H 192.168.10.1 -l 60
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    60.01     936.13

Average:        CPU     %user     %nice   %system   %iowait    %steal     %idle
Average:        all      0.24      0.00      4.17      0.01      0.00     95.58


* TEST2: vlan (.1Q) on bridge (.1ad vlan filtering) on team on igb (I350)

- before

$ netperf -t TCP_STREAM -H 192.168.10.1 -l 60
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    60.01     936.28

Average:        CPU     %user     %nice   %system   %iowait    %steal     %idle
Average:        all      0.41      0.00     11.57      0.01      0.00     88.01

- after

$ netperf -t TCP_STREAM -H 192.168.10.1 -l 60
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    60.02     935.72

Average:        CPU     %user     %nice   %system   %iowait    %steal     %idle
Average:        all      0.14      0.00      7.66      0.01      0.00     92.19


In addition to above, I tested these configurations:
- vlan (.1Q) on vlan (1.ad) on bonding on igb (I350)
- vlan (.1Q) on vlan (1.Q) on igb (I350)
- vlan (.1Q) on vlan (1.Q) on team on igb (I350)
And didn't find any problem.


[1] https://netdev01.org/sessions/18
    https://netdev01.org/docs/netdev01_bof_8021ad_makita_150212.pdf

--
- v2: Add const qualifiers for skb arguments.

Toshiaki Makita (7):
  vlan: Add features for stacked vlan device
  vlan: Introduce helper functions to check if skb is tagged
  net: Move check for multiple vlans to drivers
  net: Introduce passthru_features_check
  bonding: Don't segment multiple tagged packets on bonding device
  team: Don't segment multiple tagged packets on team device
  igb: Enable TSO for stacked vlan

 drivers/net/bonding/bond_main.c                  |  1 +
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c |  1 +
 drivers/net/ethernet/intel/igb/igb_main.c        |  1 +
 drivers/net/ethernet/mellanox/mlx4/en_netdev.c   |  1 +
 drivers/net/ethernet/qlogic/qlcnic/qlcnic_main.c |  1 +
 drivers/net/team/team.c                          |  1 +
 include/linux/if_vlan.h                          | 67 ++++++++++++++++++++++++
 include/linux/netdevice.h                        |  3 ++
 net/8021q/vlan_dev.c                             |  1 +
 net/core/dev.c                                   | 41 +++++++--------
 10 files changed, 96 insertions(+), 22 deletions(-)

-- 
1.8.1.2



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