User Manual

Driver FeaturesRev 2.2-1.0.1
Mellanox Technologies
108
ity, domains and priorities are used. Flow steering uses a methodology of flow attribute, which is
a combination of L2-L4 flow specifications, a destination QP and a priority. Flow steering rules
may be inserted either by using ethtool or by using InfiniBand verbs. The verbs abstraction uses a
different terminology from the flow attribute (
ibv_exp_flow_attr), defined by a combination of
specifications (
struct ibv_exp_flow_spec_*).
4.14.1 Enable/Disable Flow Steering
Flow Steering is disabled by default and regular L2 steering is performed instead (B0 Steering).
When using SR-IOV, flow steering is enabled if there is an adequate amount of space to store the
flow steering table for the guest/master.
 To enable Flow Steering:
Step 1. Open the /etc/modprobe.d/mlnx.conf file.
Step 2. Set the parameter log_num_mgm_entry_size to -1 by writing the option mlx4_core
log_num_mgm_entry_size=-1
.
Step 3. Restart the driver
 To disable Flow Steering:
Step 1. Open the /etc/modprobe.d/mlnx.conf file.
Step 2. Remove the options mlx4_core log_num_mgm_entry_size= -1.
Step 3. Restart the driver
4.14.2 Flow Domains and Priorities
Flow steering defines the concept of domain and priority. Each domain represents a user agent
that can attach a flow. The domains are prioritized. A higher priority domain will always super-
sede a lower priority domain when their flow specifications overlap. Setting a lower priority
value will result in higher priority
.
In addition to the domain, there is priority within each of the domains. Each domain can have at
most 2^12 priorities in accordance with its needs.
The following are the domains at a descending order of priority:
• User V
erbs allows a user application QP to be attached into a specified flow when
using
ibv_exp_create_flow and ibv_exp_destroy_flow verbs
•
ibv_ exp_ create_flow
struct ibv_exp_flow *ibv_exp_create_flow(struct ibv_qp *qp, struct ibv_exp_flow_attr
*flow)