Configuring hardware offload operations

6.10 LPAR mode z/VM guest

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

You can set the offload operations with the Linux® ethtool command. See the ethtool man page for details. The following abbreviated example shows some of the offload settings:

# ethtool -k eth0
Features for eth0:
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]
...