13. CPFL Poll Mode Driver

The [EXPERIMENTAL] cpfl PMD (librte_net_cpfl) provides poll mode driver support for Intel® Infrastructure Processing Unit (Intel® IPU) E2100. Please refer to https://www.intel.com/content/www/us/en/products/network-io/infrastructure-processing-units/asic/e2000-asic.html for more information.

13.1. Linux Prerequisites

Follow the DPDK Getting Started Guide for Linux to setup the basic DPDK environment.

To get better performance on Intel platforms, please follow the How to get best performance with NICs on Intel platforms.

13.3. Configuration

13.3.1. Runtime Configuration

  • vport (default 0)

    The PMD supports creation of multiple vports for one PCI device, each vport corresponds to a single ethdev. The user can specify the vports with specific ID to be created, and ID should be 0 ~ 7 currently, for example:

    -a ca:00.0,vport=[0,2,3]

    Then the PMD will create 3 vports (ethdevs) for device ca:00.0.

    If the parameter is not provided, the vport 0 will be created by default.

  • rx_single (default 0)

    There are two queue modes supported by Intel® IPU Ethernet E2100 Series, single queue mode and split queue mode for Rx queue.

    For the single queue model, the descriptor queue is used by SW to post buffer descriptors to HW, and it’s also used by HW to post completed descriptors to SW.

    For the split queue model, “RX buffer queues” are used to pass descriptor buffers from SW to HW, while RX queues are used only to pass the descriptor completions from HW to SW.

    User can choose Rx queue mode, example:

    -a ca:00.0,rx_single=1

    Then the PMD will configure Rx queue with single queue mode. Otherwise, split queue mode is chosen by default.

  • tx_single (default 0)

    There are two queue modes supported by Intel® IPU Ethernet E2100 Series, single queue mode and split queue mode for Tx queue.

    For the single queue model, the descriptor queue is used by SW to post buffer descriptors to HW, and it’s also used by HW to post completed descriptors to SW.

    For the split queue model, “TX completion queues” are used to pass descriptor buffers from SW to HW, while TX queues are used only to pass the descriptor completions from HW to SW.

    User can choose Tx queue mode, example:

    -a ca:00.0,tx_single=1

    Then the PMD will configure Tx queue with single queue mode. Otherwise, split queue mode is chosen by default.

13.4. Driver compilation and testing

Refer to the document Compiling and testing a PMD for a NIC for details.

13.5. Features

13.5.1. Vector PMD

Vector path for Rx and Tx path are selected automatically. The paths are chosen based on 2 conditions:

  • CPU

    On the x86 platform, the driver checks if the CPU supports AVX512. If the CPU supports AVX512 and EAL argument --force-max-simd-bitwidth is set to 512, AVX512 paths will be chosen.

  • Offload features

    The supported HW offload features are described in the document cpfl.ini, A value “P” means the offload feature is not supported by vector path. If any not supported features are used, cpfl vector PMD is disabled and the scalar paths are chosen.

13.5.2. Hairpin queue

E2100 Series can loopback packets from RX port to TX port. This feature is called port-to-port or hairpin. Currently, the PMD only supports single port hairpin.