QoS Configuration

Warning

To learn more about port QoS configuration, please refer to this community post.

Important

When working in Embedded Host mode, using mlnx_qos on both the host and Arm will result with undefined behavior. Users must only use mlnx_qos from the Arm. After changing the QoS settings from Arm, users must restart the mlx5 driver on host.

Rate Limiting Host PF and VF

From the Arm, users may limit the transmit rate of the PF in the host. For example, these commands limit the transmit rate of the PF of ECPF's p0 to 1000 Mbps and the virtual function #0 to 500 Mbps:

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            echo 1000 > /sys/class/net/p0/smart_nic/pf/max_tx_rate
echo 500 > /sys/class/net/p0/smart_nic/vf0/max_tx_rate

To set the minimum transmit rate of the PF of ECPF's p0 to 100 Mbps and of VF0 to 50 Mbps, run the following commands:

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            echo 100 > /sys/class/net/p0/smart_nic/pf/min_tx_rate"
echo 50 > /sys/class/net/p0/smart_nic/vf0/min_tx_rate"

Warning

The minimum transmit rate is implemented according to weight setting and round robin arbitration. Thus, this configuration only ensures that the minimum transmit rate of the PF is double that of VF0.

Rate Limiting SF

This section explains how to configure QoS group and SF QoS settings via mlxdevm. The settings of a QoS group include creating/deleting a QoS group and modifying its tx_max and tx_share values. The settings of SF QoS include modifying its tx_max and tx_share values, assigning SF to a QoS group and unassigning SF from a QoS group. This section focuses on the configuration syntax. Please refer to section "Limit and Bandwidth Share Per VF" in the MLNX_OFED User Manual for detailed explanation on vPort QoS behaviors.

mlxdevm Commands

mlxdevm port function rate add

	mlxdevm port function rate add <DEV>/<GROUP_NAME> Adds a QoS group.
Syntax Description	DEV/GROUP_NAME	Specifies group name in string format
Example	This command adds a new QoS group named "12_group" under device "pci/0000:03:00.0": Copy Copied! `mlxdevm port function rate add pci/0000:03:00.0/12_group`
Notes

mlxdevm port function rate del

	mlxdevm port function rate del <DEV>/<GROUP_NAME> Deletes a QoS group.
Syntax Description	DEV/GROUP_NAME	Specifies group name in string format
Example	This command deletes QoS group "12_group" from device "pci/0000:03:00.0": Copy Copied! `mlxdevm port function rate del pci/0000:03:00.0/12_group`
Notes

mlxdevm port function rate set tx_max tx_share

	mlxdevm port function rate set {<DEV>/<GROUP_NAME> \| <DEV>/<PORT_INDEX>} tx_max <TX_MAX> [tx_share <TX_SHARE>] Sets tx_max and tx_share for QoS group or mlxdevm port.
Syntax Description	DEV/GROUP_NAME	Specifies the group name to operate on
	DEV/PORT_INDEX	Specifies the mlxdevm port to operate on
	TX_MAX	tx_max bandwidth in Mb/s
	TX_SHARE	tx_share bandwidth in Mb/s
Example	This command sets tx_max to 2000Mb/s and tx_share to 500Mb/s for the "12_group" QoS group: Copy Copied! `mlxdevm port function rate set pci/0000:03:00.0/12_group tx_max 900` This command sets tx_max to 2000Mb/s and tx_share to 500Mb/s for this function: Copy Copied! `mlxdevm port function rate set pci/0000:03:00.0/229376 tx_max 2000 tx_share 500`
Notes

mlxdevm port function rate set parent

	mlxdevm port function rate set <DEV>/<PORT_INDEX> {parent <PARENT_GROUP_NAME>} Assigns mlxdevm port to a QoS group.
Syntax Description	DEV/PORT_INDEX	Specifies the mlxdevm port to operate on
Syntax Description	PARENT_GROUP_NAME	parent group name in string format
Example	This command assigns this function to the QoS group "12_group": Copy Copied! `mlxdevm port function rate set pci/0000:03:00.0/229376 parent 12_group`
Notes

mlxdevm port function rate set noparent

	mlxdevm port function rate set <DEV>/<PORT_INDEX> noparent Ungroups a mlxdevm port.
Syntax Description	DEV/PORT_INDEX	Specifies the mlxdevm port to operate on
Example	This command ungroups this function: Copy Copied! `mlxdevm port function rate set pci/0000:03:00.0/229376 noparent`
Notes

mlxdevm port function rate show

	mlxdevm port function rate show [<DEV>/<GROUP_NAME> \| <DEV>/<PORT_INDEX>] Displays QoS information QoS group or mlxdevm port.
Syntax Description	DEV/GROUP_NAME	Specifies the group name to display
Syntax Description	DEV/PORT_INDEX	Specifies the mlxdevm port to display
Example	This command displays the QoS info of all QoS groups and mlxdevm ports on the system: Copy Copied! `mlxdevm port function rate show pci/0000:03:00.0/12_group type node tx_max 1000 tx_share 200 pci/0000:03:00.0/229376 type leaf tx_max 2000 tx_share 500 parent 12_group` This command displays QoS info of 12_group: Copy Copied! `mlxdevm port function rate show pci/0000:03:00.0/12_group pci/0000:03:00.0/12_group type node tx_max 1000 tx_share 200`
Notes	If a QoS group name or mlxdevm port are not specified, all QoS groups and mlxdevm ports are displayed.

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