13. CPFL Poll Mode Driver

The 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.

  • representor (default not enabled)

    The cpfl PMD supports the creation of APF/CPF/VF port representors. Each port representor corresponds to a single function of that device. Using the devargs option representor the user can specify which functions to create port representors.

    Format is:

    [[c<controller_id>]pf<pf_id>]vf<vf_id>

    Controller_id 0 is host (default), while 1 is accelerator core. Pf_id 0 is APF (default), while 1 is CPF. Default value can be omitted.

    Create 4 representors for 4 vfs on host APF:

    -a BDF,representor=c0pf0vf[0-3]

    Or:

    -a BDF,representor=pf0vf[0-3]

    Or:

    -a BDF,representor=vf[0-3]

    Create a representor for CPF on accelerator core:

    -a BDF,representor=c1pf1

    Multiple representor devargs are supported. Create 4 representors for 4 vfs on host APF and one representor for CPF on accelerator core:

    -a BDF,representor=vf[0-3],representor=c1pf1

  • flow_parser (default not enabled)

    The cpfl PMD supports utilizing a JSON config file to translate rte_flow tokens into low-level hardware resources.

    The JSON configuration file is provided by the hardware vendor and is intended to work exclusively with a specific P4 pipeline configuration, which must be compiled and programmed into the hardware.

    The format of the JSON file strictly follows the internal specifications of the hardware vendor and is not meant to be modified directly by users.

    Using the devargs option flow_parser the user can specify the path of a json file, for example:

    -a ca:00.0,flow_parser="refpkg.json"

    Then the PMD will load json file for device ca:00.0. The parameter is optional.

    As CPFL PMD can run on both XEON host and IPU’s compute complex, the driver dynamically detects which system type it is running on by querying the hostname.

13.4. Driver compilation and testing

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

The jansson library must be installed to use rte_flow.

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.

13.5.3. Flow offload

PMD uses a json file to direct CPF PMD to parse rte_flow tokens into low level hardware resources.

  • Required Libraries

    • jansson
      • For Ubuntu, it can be installed using apt install libjansson-dev

  • run testpmd with the json file, create two vports

    dpdk-testpmd -c 0x3 -n 4 -a 0000:af:00.6,vport=[0-1],flow_parser="refpkg.json" -- -i

  1. Create one flow to forward ETH-IPV4-TCP from I/O port to a local(CPF’s) vport. Flow should be created on vport X. Group M should match fxp module. Action port_representor Y means forward packet to local vport Y:

    .. code-block:: console

    flow create X ingress group M pattern eth dst is 00:01:00:00:03:14 / ipv4 src is 192.168.0.1 dst is 192.168.0.2 / tcp / end actions port_representor port_id Y / end

  2. Send a matched packet, and it should be displayed on PMD:

    .. code-block:: console

    sendp(Ether(dst=‘00:01:00:00:03:14’)/IP(src=‘192.168.0.1’,dst=‘192.168.0.2’)/TCP(),iface=”ens25f0”)