AB287A PCI-X 10 Gigabit Ethernet Card Overview

Product Overview

10 Gigabit Ethernet Link Settings

lanadmin -X recv_cko_on/off ppa

TCP Segmentation Offload

TCP Segmentation Offload (TSO) is enabled by default; so, there is no need to enable it. TSO offloads outbound

TCP-segmentation processing to reduce CPU utilization. It allows TCP to send larger segments to the LAN card, which will

then segment them to sizes appropriate for the link MTU. This can reduce the server’s load for certain applications which

primarily transmit large amounts of data. Not all applications benefit from TSO. Only data intensive applications that transmit

large data buffers using TCP over IPv4 are improved. Systems that support hardware partitioning decrease their per-card

throughput yet significantly reduce CPU utilization.

TSO is enabled by default. To change the TSO setting on each specific interface, use an editor such as “vi” to edit the

configuration file, /etc/rc.config.d/hpixgbeconf. This is the best way to save the configuration across reboots.

Alternatively, you can use the lanadmin command to temporarily set the “vmtu” tunable to a non-zero value. Using

lanadmin, though, will not preserve the configuration value when the system is rebooted.

• The following command will list the TSO capability of the link:

# lanadmin –x vmtu ppa

Driver/Hardware supports TCP Segmentation Offload. Current VMTU = 0.

• The syntax of the command to temporarily set the vmtu is as follows (note: the X is capitalized):

# lanadmin -X vmtu new_vmtu_value ppa

NOTE Currently only two values are allowed for the tunable “vmtu”: 0 and 32160. Setting “vmtu” to 0 disables

the TSO feature, and setting it to 32160 enables it.

• When TSO is enabled, the output looks like:

# lanadmin –x vmtu ppa

Driver/Hardware supports TCP Segmentation Offload. Current VMTU = 32160.