NIC Queue Configuration¶

Overview ¶

NIC channels (queues) can be configured per interface on systems with multiple network interfaces. By default, the number of NIC queues is configured automatically on a system as follows:

Platform interfaces (oam, management/admin, cluster-host)

The number of queues is configured to match the number of platform CPUs.
SRIOV interfaces
- The number of PF queues is configured to match the number of application CPUs.
- The number of VF queues is determined by the driver. The number allocated to each VF can vary based on how many VFs are configured on the PF.

Interface API and Command Line Interface Considerations ¶

The following attributes are available on the interface resource for configuring NIC channels.

Attribute	Type	Description
`channels`	Integer or null	Number of NIC channels (queues) for SR-IOV PF. Applicable to `iftype: ethernet` or `iftype: ae`. Must be ≥ 1 and ≤ port’s `maxchannels`. `null` = system defaults. Modifiable at runtime without host lock.
`sriov_vf_channels`	Integer or null	Number of SR-IOV VF channels (queues). Applicable to `ifclass: pci-sriov` with `sriov_vf_driver: netdevice`, or `iftype: vf`. Must be ≥ 1 and ≤ port’s `sriov_vf_maxchannels`. `null` = system defaults. Modifiable at runtime without host lock.

These attributes appear in:

API Operation	System Command
List interfaces	`system host-if-list <host>` — `channels` and `sriov_vf_channels` shown in the Attribute column when non-null
Show interface	`system host-if-show <host> <interface>` — `channels` and `sriov_vf_channels` displayed as dedicated fields
Create interface	`system host-if-add <host> <ifname> <iftype> ... --channels <N> --vf-channels <N>`
Modify interface	`system host-if-modify <host> <interface> --channels <N>` or `--vf-channels <N>`
Reset to defaults	`system host-if-modify <host> <interface> --channels none` or `--vf-channels none` (also accepts `default`)

Port API and Command Line Interface Considerations ¶

The following read-only attributes are present on the port resource:

Attribute	Type	Description
`numchannels`	Integer	Current number of combined channels configured on the physical port.
`maxchannels`	Integer	Maximum combined channels supported by hardware (upper bound for interface channels).
`sriov_vf_numchannels`	Integer	Current number of channels on each SR-IOV VF.
`sriov_vf_maxchannels`	Integer	Maximum channels per VF (upper bound for interface `sriov_vf_channels`).

These attributes appear in:

API Operation	System Command
Show port	`system host-port-show <host> <port>` — all four fields displayed

Relationship Between Port and Interface Fields ¶

The following table describes how port attributes map to their corresponding interface attributes.

Port	Interface
`maxchannels`	`channels` must be ≤ this value
`numchannels`	actual applied value
`sriov_vf_maxchannels`	`sriov_vf_channels` must be ≤ this value
`sriov_vf_numchannels`	actual applied value

NIC Channel Configuration Validation Rules ¶

The following validation rules are enforced server-side:

channels cannot be set on VLAN interfaces or iftype: vf.
sriov_vf_channels requires ifclass: pci-sriov with sriov_vf_driver: netdevice, or iftype: vf.
Values must be ≥ 1.
Values cannot exceed the corresponding port maximum.
Changes are applied at runtime (no host lock/unlock required).
Setting none or default resets to system-calculated defaults (platform CPUs for platform interfaces, application CPUs for SR-IOV PFs).

Configure NIC Channels on an Interface ¶

To configure NIC channels on an interface, perform the following steps:

Procedure

Check the current and maximum channels allowed on the port.
```
~(keystone_admin)]$ system host-port-show <host> <port>
```

Set the number of channels for a platform classed interface.

~(keystone_admin)]$ system host-if-modify <host> <interface> --channels <N>

Set the number of channels for the PF and optionally for the associated VFs, for a pci-sriov classed interface.

~(keystone_admin)]$ system host-if-modify <host> <interface> --channels <N>
~(keystone_admin)]$ system host-if-modify <host> <interface> --vf-channels <N>

Wait for the runtime manifest to perform the configuration, then check the values again.