User Manual

Driver FeaturesRev 2.1-1.0.6

Mellanox Technologies

All packets that contain the above destination MAC address are to be steered into rx-ring 2 (its

underlying QP), with priority 5 (within the ethtool domain)

• ethtool –U eth5 flow-type tcp4 src-ip 1.2.3.4 dst-port 8888 loc 5 action 2

All packets that contain the above destination IP address and source port are to be steered into rx-

ring 2. When destination MAC is not given, the user's destination MAC is filled automatically.

• ethtool –u eth5

Shows all of ethtool’s steering rule

When configuring two rules with the same priority, the second rule will overwrite the first one, so this

ethtool interface is effectively a table. Inserting Flow Steering rules in the kernel requires support

from both the ethtool in the user space and in kernel (v2.6.28).

MLX4 Driver Support

The mlx4 driver supports only a subset of the flow specification the ethtool API defines. Asking for

an unsupported flow specification will result with an “invalid value” failure.

The following are the flow specific parameters:

• RFS

RFS is an in-kernel-logic responsible for load balancing between CPUs by attaching flows to CPUs

that are used by flow’s owner applications. This domain allows the RFS mechanism to use the flow

steering infrastructure to support the RFS logic by implementing the

ndo_rx_flow_steer, which, in

turn, calls the underlying flow steering mechanism with the RFS domain.

Enabling the RFS requires enabling the

‘ntuple’ flag via the ethtool,

For example, to enable ntuple for eth0, run:

RFS requires the kernel to be compiled with the

CONFIG_RFS_ACCEL option. This options is available

in kernels 2.6.39 and above. Furthermore, RFS requires Device Managed Flow Steering support.

• All of the rest

The lowest priority domain serves the following users:

• The mlx4 Ethernet driver attaches its unicast and multicast MACs addresses to its QP

using L2 flow specifications

Table 5 - Flow Specific Parameters

ether tcp4/udp4 ip4

Mandatory dst src-ip/dst-ip

Optional vlan src-ip, dst-ip, src-

port, dst-port, vlan

src-ip, dst-ip, vlan

ethtool -K eth0 ntuple on

RFS cannot function if LRO is enabled. LRO can be disabled via ethtool.