[net-next,0/2] net: enetc: add support for software TSO

Message

Ioana Ciornei Oct. 6, 2021, 8:13 p.m. UTC

This series adds support for driver level TSO in the enetc driver.

Ever since the ENETC MDIO erratum workaround is in place, the Tx path is
incurring a penalty (enetc_lock_mdio/enetc_unlock_mdio) for each skb to
be sent out. On top of this, ENETC does not support Tx checksum
offloading. This means that software TSO would help performance just by
the fact that one single mdio lock/unlock sequence would cover multiple
packets sent. On the other hand, checksum needs to be computed in
software since the controller cannot handle it.

This is why, beside using the usual tso_build_hdr()/tso_build_data()
this specific implementation also has to compute the checksum, both IP
and L4, for each resulted segment.

Even with that, the performance improvement of a TCP flow running on a
single A72@1.3GHz of the LS1028A SoC (2.5Gbit/s port) is the following:

before: 1.63 Gbits/sec
after:  2.34 Gbits/sec

Ioana Ciornei (2):
  net: enetc: declare NETIF_F_IP_CSUM and do it in software
  net: enetc: add support for software TSO

 drivers/net/ethernet/freescale/enetc/enetc.c  | 272 +++++++++++++++++-
 drivers/net/ethernet/freescale/enetc/enetc.h  |   4 +
 .../net/ethernet/freescale/enetc/enetc_pf.c   |   7 +-
 .../net/ethernet/freescale/enetc/enetc_vf.c   |   7 +-
 4 files changed, 279 insertions(+), 11 deletions(-)