Work with DPDK

This page describes how to use the Data Plane Development Kit (DPDK) on U4C Compute Engine instances.

About DPDK on U4C instances

The Data Plane Development Kit (DPDK) is a framework for performance-intensive applications that require fast packet processing, low latency, and consistent performance. DPDK bypasses the Linux kernel network stack and runs directly in the user space.

U4C instances support DPDK using the Google Virtual NIC (gVNIC) Poll Mode Driver (PMD). Once you install DPDK, driver features can be configured using standard ethdev and rte_flow APIs.

Using DPDK with ULL Solution includes support for flow steering. You can bypass default Receive Side Scaling (RSS) hashing by steering specific traffic flows directly to a designated receive queue (RX). ULL Solution supports 3-tuple flow steering (protocol, destination IP address, and destination port) for ULL unicast and multicast traffic.

Additionally, the gVNIC PMD supports hardware RX timestamping in mbufs and clock reads through rte_eth_read_clock.

Limitations

Using DPDK on U4C instances has the following limitations:

  • Support for bare metal instances isn't available in the mainline DPDK release or the dpdk-next-net repository. You must apply the required patches by following the steps in Install DPDK on your U4C instance.
  • When configuring accurate time for a U4C instance that uses DPDK on its ULL network interfaces (nic1 and nic2), you must configure chrony to use nic0 as source for time synchronization.

Before you begin

Before you work with DPDK on U4C Compute Engine instances, you must meet the following requirements.

Create a U4C instance

If you haven't already, create a U4C bare metal instance. See Create ULL Compute Engine instances.

Connect to your instance by using SSH

If you haven't already, connect to your instance by using SSH.

Install DPDK on your U4C instance

To install DPDK on your U4C instance, follow these steps:

  1. Configure the dependencies for DPDK installation:

    1. If you are using Rocky Linux, enable the CodeReady Builder (CRB) repository. If you are using Red Hat Enterprise Linux (RHEL), skip this step.

      sudo dnf -y config-manager --enable crb

    2. Install the required packages and build tools:

      sudo dnf install -y git gcc gcc-c++ make ninja-build python3-pip \
    kernel-devel-$(uname -r) pkgconf-pkg-config numactl-devel
sudo pip install pyelftools meson

  2. Download the DPDK source. You must use either the dpdk-next-net repository or the DPDK release version 26.07 or later.

    • dpdk-next-net

      git clone git://dpdk.org/next/dpdk-next-net dpdk-source

    • DPDK 26.07 or later

      git clone git://dpdk.org/dpdk -b v26.07 dpdk-source

  3. Apply the required patches. The source for bare metal support is hosted in the dpdk-bm branch of the Google compute-virtual-ethernet-dpdk repository. The patches are ABI-compatible with the dpdk-next-net repository.

    You can apply the patches using either a verbatim copy or a cherry-pick method. Do one of the following depending on your preferred workflow:

    • Verbatim copy

      git clone https://github.com/google/compute-virtual-ethernet-dpdk -b dpdk-bm dpdk-bm
cp -r dpdk-bm/drivers/net/gve/* dpdk-source/drivers/net/gve/
cd dpdk-source

    • Cherry-pick

      cd dpdk-source
git remote add gve-bm https://github.com/google/compute-virtual-ethernet-dpdk
git fetch gve-bm
git cherry-pick gve-bm/main..gve-bm/dpdk-bm

  4. Build and install DPDK:

    meson setup build
sudo ninja -C build install; sudo ldconfig

Bind DPDK to a driver

You must bind your instance's network interfaces to a DPDK-compatible kernel driver as described in Bind DPDK to a driver and test it.

For U4C bare metal instances, consider the following:

  • Bare metal instances don't require the UIO or IOMMU-less VFIO drivers used by VM instances. You can bind directly to the standard vfio-pci driver.
  • You can only bind the ULL network interfaces (nic1 and nic2) to the DPDK driver. nic0 must remain bound to the standard kernel driver to maintain network connectivity and support time synchronization.

For more information, see Binding and Unbinding Network Ports to/from the Kernel Modules in the DPDK documentation.

What's next