How to Get DPDK with pdump Running

The purpose of this experiment is to get Intel’s DPDK framework up and running on a server.

Useful Materials

My Environment

I am running a Dell R940 with Napatech Card NT200A02

CentOS Release Info

    NAME="CentOS Linux"
    VERSION="7 (Core)"
    ID="centos"
    ID_LIKE="rhel fedora"
    VERSION_ID="7"
    PRETTY_NAME="CentOS Linux 7 (Core)"
    ANSI_COLOR="0;31"
    CPE_NAME="cpe:/o:centos:centos:7"
    HOME_URL="https://www.centos.org/"
    BUG_REPORT_URL="https://bugs.centos.org/"

    CENTOS_MANTISBT_PROJECT="CentOS-7"
    CENTOS_MANTISBT_PROJECT_VERSION="7"
    REDHAT_SUPPORT_PRODUCT="centos"
    REDHAT_SUPPORT_PRODUCT_VERSION="7"

    CentOS Linux release 7.7.1908 (Core)
    CentOS Linux release 7.7.1908 (Core)

Kernel Info

Linux r940.lan 3.10.0-1062.4.3.el7.x86_64 #1 SMP Wed Nov 13 23:58:53 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

Physical Setup

Installation NapaTech Driver

Install Driver

Download the Napatech software from here
Run yum groupinstall "Development Tools" && yum install -y kernel-devel gettext-devel openssl-devel perl-CPAN perl-devel zlib-devel pciutils && yum install -y https://centos7.iuscommunity.org/ius-release.rpm && yum remove -y git && yum install -y git2u-all
Unzip and run package_install_3gd.sh

Install DPDK

export NAPATECH3_PATH=/opt/napatech3
Download with git clone https://github.com/napatech/dpdk.git
Edit the security limits with vim /etc/security/limits.conf. After making the below edits you will need to log out and log back in for them to take effect. 1.Add the following lines at the end of the file. This assumes you are running as root:
```
         root    hard   memlock           unlimited
         root    soft   memlock           unlimited
```
Run yum install -y gcc numactl-devel kernel-devel pciutils elfutils-libelf-devel make libpcap python3 tar vim wget tmux vim mlocate hwloc libpcap-devel python36-devel
Extract dpdk and cd into its directory
set the environment variable RTE_SDK. It is the directory in which you extracted all the DPDK files. export RTE_SDK=<YOUR_DIR>
Run make config T=x86_64-native-linuxapp-gcc install CONFIG_RTE_LIBRTE_PMD_PCAP=y CONFIG_RTE_LIBRTE_PDUMP=y DESTDIR=install CONFIG_RTE_LIBRTE_PMD_NTACC=y to build dpdk. Ensure your install directory exists.
make -j

NOTE: The option CONFIG_RTE_LIBRTE_PMD_PCAP=y enabled libpcap support in DPDK. This is required for pdump to work.

Once an DPDK target environment directory has been created (such as x86_64-native-linux-gcc), it contains all libraries and header files required to build an application. When compiling an application in the Linux* environment on the DPDK, the following variables must be exported:

RTE_TARGET - Points to the DPDK target environment directory.

  export RTE_TARGET=/opt/dpdk-19.08/x86_64-native-linux-gcc

You may want to add this variable and RTE_SDK to ~/.bash_profile

Update Your Bash Profile

Add:

    export RTE_SDK=/opt/dpdk
    export NAPATECH3_PATH=/opt/napatech3
    export RTE_TARGET=/opt/dpdk/x86_64-native-linuxapp-gcc

to ~/.bash_profile

Install ELF Tools

Run the following:

    pip3 install numpy
    pip3 install elftools
    pip3 install pyelftools

Configuration

Configure Ports

Move to your dpdk dir and run ./install/share/dpdk/usertools/dpdk-setup.sh. This should give you a menu with all available DPDK options. The menu is setup in such a way that you must perform each step listed in the menu. If things have gone correctly to this point your Step 1 should look like the following:
```
 ----------------------------------------------------------
 Step 1: Select the DPDK environment to build
 ----------------------------------------------------------
 [1] *
```

My menu looks like this:

 ----------------------------------------------------------
 Step 1: Select the DPDK environment to build
 ----------------------------------------------------------
 [1] *

 ----------------------------------------------------------
 Step 2: Setup linux environment
 ----------------------------------------------------------
 [2] Insert IGB UIO module
 [3] Insert VFIO module
 [4] Insert KNI module
 [5] Setup hugepage mappings for non-NUMA systems
 [6] Setup hugepage mappings for NUMA systems
 [7] Display current Ethernet/Baseband/Crypto device settings
 [8] Bind Ethernet/Baseband/Crypto device to IGB UIO module
 [9] Bind Ethernet/Baseband/Crypto device to VFIO module
 [10] Setup VFIO permissions

 ----------------------------------------------------------
 Step 3: Run test application for linux environment
 ----------------------------------------------------------
 [11] Run test application ($RTE_TARGET/app/test)
 [12] Run testpmd application in interactive mode ($RTE_TARGET/app/testpmd)

 ----------------------------------------------------------
 Step 4: Other tools
 ----------------------------------------------------------
 [13] List hugepage info from /proc/meminfo

 ----------------------------------------------------------
 Step 5: Uninstall and system cleanup
 ----------------------------------------------------------
 [14] Unbind devices from IGB UIO or VFIO driver
 [15] Remove IGB UIO module
 [16] Remove VFIO module
 [17] Remove KNI module
 [18] Remove hugepage mappings

 [19] Exit Script

Next run option 6 to instert huge pages for NUMA systems. Notice you will be prompted to select an amount of memory on a per processor basis. This is because there are pages associated with each individual processor to increase performance via locality. I used a value of 4096 for each NUMA node.

Performing Packet Capture

Setup the NapaTech Card

Initial Setup

Get the core layout with ./install/share/dpdk/usertools/cpu_layout.py View your port layout with ./install/share/dpdk/usertools/dpdk-devbind.py -s

Starting testpmd

NOTE: The -- separates the argumentsn for the EAL vs TestPMD.

    ./install/bin/testpmd -l 0,4,8,12,16,20,24,28,32,36 -n 4 -- -i

After testpmd has started don’t forget to run the start command on the testpmd command line.

pdump

    ./install/bin/dpdk-pdump -- --pdump 'device_id=0000:5b:00.0,queue=*,rx-dev=/tmp/capture.pcap'

Helpful Tips

NapaTech

Detecting Installed Cards

    /opt/napatech3/bin/imgctrl -q

Load the Driver

    /opt/napatech3/bin/ntload.sh

Run the ntserver

    /opt/napatech3/bin/ntstart.sh

Show Interface Info

    /opt/napatech3/bin/adapterinfo

Getting CPU Info

DPDK provides a tool for seeing the CPU layout with ./install/share/dpdk/usertools/cpu_layout.py You can see the logical layout of the cores with cat /proc/cpuinfo You can alse run lstopo-no-graphics

Notice that the cores alternate back and forth.

Process Types in DPDK

DPDK runs two different types of processes. There are as follows:

primary processes, which can initialize and which have full permissions on shared memory
secondary processes, which cannot initialize shared memory, but can attach to pre- initialized shared memory and create objects in it.

Standalone DPDK processes are primary processes, while secondary processes can only run alongside a primary process or after a primary process has already configured the hugepage shared memory for them.

TestPMD

The test pmd manual is available here

Interactive Commands

Starting transmit

    start

Get Port Info

    show port info all

Forwarding Modes

TestPMD has different forwarding modes that can be used within the application.

Input/output mode: This mode is generally referred to as IO mode. It is the most common forwarding mode and is the default mode when TestPMD is started. In IO mode a CPU core receives packets from one port (Rx) and transmits them to another port (Tx). The same port can be used for reception and transmission if required.
Rx-only mode: In this mode the application polls packets from the Rx ports and frees them without transmitting them. In this way it acts as a packet sink.
Tx-only mode: In this mode the application generates 64-byte IP packets and transmits them from the Tx ports. It doesn’t handle the reception of packets and as such acts as a packet source. These latter two modes (Rx-only and Tx-only) are useful for checking packet reception and transmission separately.

Apart from these three modes there are other forwarding modes that are explained in the TestPMD documentation.

Port Topology Modes

In paired mode, the forwarding is between pairs of ports, for example: (0,1), (2,3), (4,5).

In chained mode, the forwarding is to the next available port in the port mask, for example: (0,1), (1,2), (2,0). The ordering of the ports can be changed using the portlist testpmd runtime function.

In loop mode, ingress traffic is simply transmitted back on the same interface.

Receive Side Scaling

=Receive-Side Scaling (RSS), also known as multi-queue receive, distributes network receive processing across several hardware-based receive queues, allowing inbound network traffic to be processed by multiple CPUs. RSS can be used to relieve bottlenecks in receive interrupt processing caused by overloading a single CPU, and to reduce network latency.

To determine whether your network interface card supports RSS, check whether multiple interrupt request queues are associated with the interface in /proc/interrupts. For example, if you are interested in the p1p1 interface:

    # egrep 'CPU|p1p1' /proc/interrupts
    CPU0    CPU1    CPU2    CPU3    CPU4    CPU5
    89:   40187       0       0       0       0       0   IR-PCI-MSI-edge   p1p1-0
    90:       0     790       0       0       0       0   IR-PCI-MSI-edge   p1p1-1
    91:       0       0     959       0       0       0   IR-PCI-MSI-edge   p1p1-2
    92:       0       0       0    3310       0       0   IR-PCI-MSI-edge   p1p1-3
    93:       0       0       0       0     622       0   IR-PCI-MSI-edge   p1p1-4
    94:       0       0       0       0       0    2475   IR-PCI-MSI-edge   p1p1-5

huge pages https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/performance_tuning_guide/sect-red_hat_enterprise_linux-performance_tuning_guide-memory-configuring-huge-pages