Configuring hardware offload operations
Some CPU-intensive operations can be offloaded to the OSA adapter, thus reducing the load on the host CPU.
The qeth device driver supports offloading for the
following operations on both layer 2 and layer 3:
- Inbound (receive) and outbound (transmit) checksum calculations for TCP and UDP network packets
- TCP segmentation, see Enabling and disabling TCP segmentation offload.
VLAN interfaces inherit offload settings from their base interface.
You can set the offload operations with the Linux
ethtool command. See the ethtool man page for details. The
following abbreviated example shows shows some offload settings:
# ethtool -k encf500
Features for encf500:
rx-checksumming: on
tx-checksumming: on
tx-checksum-ipv4: on
tx-checksum-ip-generic: off [fixed]
tx-checksum-ipv6: on
tx-checksum-fcoe-crc: off [fixed]
tx-checksum-sctp: off [fixed]
scatter-gather: on
tx-scatter-gather: on
tx-scatter-gather-fraglist: off [fixed]
tcp-segmentation-offload: on
tx-tcp-segmentation: on
tx-tcp-ecn-segmentation: off [fixed]
tx-tcp6-segmentation: on
udp-fragmentation-offload: off [fixed]
generic-segmentation-offload: off [requested on]
generic-receive-offload: on
large-receive-offload: off [fixed]
...