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 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
