idpf Linux* Base Driver for the Intel(R) Infrastructure Data Path Function ¶

The idpf driver serves as both the Physical Function (PF) and Virtual Function (VF) driver for the Intel(R) Infrastructure Data Path Function.

Driver information can be obtained using ethtool, lspci, and ip.

For questions related to hardware requirements, refer to the documentation supplied with your Intel adapter. All hardware requirements listed apply to use with Linux.

Identifying Your Adapter ¶

For information on how to identify your adapter, and for the latest Intel network drivers, refer to the Intel Support website: http://www.intel.com/support

Additional Features and Configurations ¶

The driver utilizes the ethtool interface for driver configuration and diagnostics, as well as displaying statistical information. The latest ethtool version is required for this functionality. If you don’t have one yet, you can obtain it at: https://kernel.org/pub/software/network/ethtool/

Viewing Link Messages ¶

Link messages will not be displayed to the console if the distribution is restricting system messages. In order to see network driver link messages on your console, set dmesg to eight by entering the following:

# dmesg -n 8

Note

This setting is not saved across reboots.

Jumbo Frames ¶

Jumbo Frames support is enabled by changing the Maximum Transmission Unit (MTU) to a value larger than the default value of 1500.

Use the ip command to increase the MTU size. For example, enter the following where <ethX> is the interface number:

# ip link set mtu 9000 dev <ethX>
# ip link set up dev <ethX>

Note

The maximum MTU setting for jumbo frames is 9706. This corresponds to the maximum jumbo frame size of 9728 bytes.

Note

This driver will attempt to use multiple page sized buffers to receive each jumbo packet. This should help to avoid buffer starvation issues when allocating receive packets.

Note

Packet loss may have a greater impact on throughput when you use jumbo frames. If you observe a drop in performance after enabling jumbo frames, enabling flow control may mitigate the issue.

Performance Optimization ¶

Driver defaults are meant to fit a wide variety of workloads, but if further optimization is required, we recommend experimenting with the following settings.

Interrupt Rate Limiting ¶

This driver supports an adaptive interrupt throttle rate (ITR) mechanism that is tuned for general workloads. The user can customize the interrupt rate control for specific workloads, via ethtool, adjusting the number of microseconds between interrupts.

To set the interrupt rate manually, you must disable adaptive mode:

# ethtool -C <ethX> adaptive-rx off adaptive-tx off

For lower CPU utilization:

Disable adaptive ITR and lower Rx and Tx interrupts. The examples below affect every queue of the specified interface.
Setting rx-usecs and tx-usecs to 80 will limit interrupts to about 12,500 interrupts per second per queue:
```
# ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 80
tx-usecs 80
```

For reduced latency:

Disable adaptive ITR and ITR by setting rx-usecs and tx-usecs to 0 using ethtool:
```
# ethtool -C <ethX> adaptive-rx off adaptive-tx off rx-usecs 0
tx-usecs 0
```

Per-queue interrupt rate settings:

The following examples are for queues 1 and 3, but you can adjust other queues.
To disable Rx adaptive ITR and set static Rx ITR to 10 microseconds or about 100,000 interrupts/second, for queues 1 and 3:
```
# ethtool --per-queue <ethX> queue_mask 0xa --coalesce adaptive-rx off
rx-usecs 10
```

To show the current coalesce settings for queues 1 and 3:

# ethtool --per-queue <ethX> queue_mask 0xa --show-coalesce

Virtualized Environments ¶

In addition to the other suggestions in this section, the following may be helpful to optimize performance in VMs.

Using the appropriate mechanism (vcpupin) in the VM, pin the CPUs to individual LCPUs, making sure to use a set of CPUs included in the device’s local_cpulist: /sys/class/net/<ethX>/device/local_cpulist.
Configure as many Rx/Tx queues in the VM as available. (See the idpf driver documentation for the number of queues supported.) For example:
# ethtool -L <virt_interface> rx <max> tx <max>

Support ¶

For general information, go to the Intel support website at: http://www.intel.com/support/

If an issue is identified with the released source code on a supported kernel with a supported adapter, email the specific information related to the issue to intel-wired-lan@lists.osuosl.org.

Trademarks ¶

Intel is a trademark or registered trademark of Intel Corporation or its subsidiaries in the United States and/or other countries.

Other names and brands may be claimed as the property of others.