Intel® Ethernet 800 Series Linux Flow Control
Configuration Guide for RDMA Use Cases
LFC Setup Instructions
Configuring LFC on an
- If your hosts are connected through a switch, you must also enable flow control on the switch ports.
- If your hosts are connected back-to-back, enable LFC on both adapters.
The examples below use eth0 as the
Switch settings vary by manufacturer. In your switch manual, look for syntax containing words like: flowcontrol, flow-control, tx-pause, or rx-pause.
To enable LFC on your network:
- Disable firmware-based DCB on the adapter.
# ethtool --set-priv-flags <interface> fw-lldp-agent off - Verify that firmware DCB is disabled.
# ethtool --show-priv-flags <interface> | grep fw-lldp-agent fw-lldp-agent : off - Ensure that lldpad is not running.
# ps -ef | grep lldpad - Disable PFC on your switch, if applicable (show PFC status per port).
switch>show priority-flow-control For example, disable PFC on a given port (like port 31/1) on an Arista 7060CX:
switch>enable switch#configure switch(config)#interface Ethernet 31/1 switch(config-if-Et31/1)#no priority-flow-control Note:Some switches allow for a range of ports to be specified, for example 1/1-32/1. - Enable link-level flow control on the adapter.
# ethtool -A eth0 rx on tx on - Check LFC settings on the adapter.
# ethtool -a eth0 Pause parameters for eth0: Autonegotiate: on RX: on TX: on RX negotiated: on TX negotiated: on - Enable flow control on the switch ports.
For example, enable Rx and Tx flow control on switch port 21 on an Arista 7060CX:
switch>enable switch#configure switch(config)#interface Ethernet 21/1 switch(config-if-Et31/1)#flowcontrol receive on switch(config-if-Et31/1)#flowcontrol send on - Check LFC settings on the switch.
For example, show flow control settings on ports 21-22 on an Arista 7060CX:
Switch(config-if-Et31/1)#show interfaces ethernet 21/1-22/1 flowcontrol Port Send FlowControl Receive FlowControl RxPause TxPause admin oper admin oper ---------- -------- -------- -------- -------- ------------- ------------- Et21/1 on on off off 170373384 0 Et22/1 on on off off 289143370 0