This patch enables TSO support for non-DPDK use cases, and
also add check-system-tso testsuite. Before TSO, we have to
disable checksum offload, allowing the kernel to calculate the
TCP/UDP packet checsum. With TSO, we can skip the checksum
validation by enabling checksum offload, and with large packet
size, we see better performance.
Consider container to container use cases:
iperf3 -c (ns0) -> veth peer -> OVS -> veth peer -> iperf3 -s (ns1)
And I got around 6Gbps, similar to TSO with DPDK-enabled.
Acked-by: Flavio Leitner <fbl@sysclose.org>
Acked-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: William Tu <u9012063@gmail.com>
Abbreviated as TSO, TCP Segmentation Offload is a feature which enables
the network stack to delegate the TCP segmentation to the NIC reducing
the per packet CPU overhead.
A guest using vhostuser interface with TSO enabled can send TCP packets
much bigger than the MTU, which saves CPU cycles normally used to break
the packets down to MTU size and to calculate checksums.
It also saves CPU cycles used to parse multiple packets/headers during
the packet processing inside virtual switch.
If the destination of the packet is another guest in the same host, then
the same big packet can be sent through a vhostuser interface skipping
the segmentation completely. However, if the destination is not local,
the NIC hardware is instructed to do the TCP segmentation and checksum
calculation.
It is recommended to check if NIC hardware supports TSO before enabling
the feature, which is off by default. For additional information please
check the tso.rst document.
Signed-off-by: Flavio Leitner <fbl@sysclose.org>
Tested-by: Ciara Loftus <ciara.loftus.intel.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
