Multi Channel DMA Intel® FPGA IP for PCI Express* Design Example User Guide

ID 683517
Date 6/09/2025
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

3.5.7. Set the Boot Parameters

Follow the steps below to modify the default hugepages setting in the grub files:
  1. Edit the /etc/default/grub file.

    Append the highlighted parameters to the GRUB_CMDLINE_LINUX line in the /etc/default/grub file.

    For Intel CPU:

    GRUB_CMDLINE_LINUX="default_hugepagesz=1G hugepagesz=1G hugepages=20 intel_iommu=on iommu=pt processor.max_cstate=0 intel_idle.max_cstate=0 intel_pstate=disable panic=1 quiet splash vt.handoff=7"

    For AMD CPU:

    GRUB_CMDLINE_LINUX="default_hugepagesz=1G hugepagesz=1G hugepages=20 amd_iommu=on iommu=soft processor.max_cstate=0 amd-pstate panic=1 quiet splash vt.handoff=7"

    An Intel CPU example of the /etc/default/grub file on Ubuntu after the edits can be seen below:

    root@bapvecise042:~# cat /etc/default/grub # If you change this file, run 'update-grub' afterwards to update 
    # /boot/grub/grub.cfg. 
    # For full documentation of the options in this file, see: 
    #   info -f grub -n 'Simple configuration' 
    GRUB_DEFAULT="1>2" GRUB_TIMEOUT_STYLE=hidden 
    GRUB_TIMEOUT=0 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` 
    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" 
    GRUB_CMDLINE_LINUX="default_hugepagesz=1G hugepagesz=1G hugepages=20 intel_iommu=on iommu=pt nprocessor.max_cstate=0 
    intel_idle.max_cstate=0 intel_pstate=disable panic=1 quiet splash vt.handoff=7"
    # Uncomment to enable BadRAM filtering, modify to suit your needs 
    # This works with Linux (no patch required) and with any kernel that obtains 
    # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) 
    #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" 
    # Uncomment to disable graphical terminal (grub-pc only) 
    #GRUB_TERMINAL=console 
    # The resolution used on graphical terminal 
    # note that you can use only modes which your graphic card supports via VBE 
    # you can see them in real GRUB with the command `vbeinfo' 
    #GRUB_GFXMODE=640x480 
    # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux 
    #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries 
    #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start 
    #GRUB_INIT_TUNE="480 440 1" 
    
  2. Generate GRUB configuration files.

    Execute the following command:

    sudo update-grub

  3. Reboot the system.
  4. Verify the changes above by running the following command:

    $ cat /proc/cmdline

  5. Set the hugepages:

    $ echo 40 | sudo tee /proc/sys/vm/nr_hugepages

  6. If the host supports multiple NUMAs, use the following steps:
    1. Check how many NUMAs are enabled on the host.
      $lscpu | grep NUMA
      NUMA node(s): 2
      NUMA node0 CPU(s): 0-15, 32-47
      NUMA node1 CPU(s): 16-31, 48-63
      

      In this example, we have two NUMAs. If only one NUMA is present, ignore the below steps:

    2. Check which device is provisioned:
      $cat /sys/class/pci_bus/<Domain:Bus>/device/numa_node
      
    3. Enable the hugepages, whichever NUMA device is located:
      $echo 40 |> sudo tee /sys/devices/system/node/node<nodenum>\
      /hugepages/hugepages-1048576kB/nr_hugepages
      
    4. Configure the thread sequence in software/user/cli/perfq_app/perfq_app.h based on which NUMA device is located. For example:

      #define THREAD_SEQ "0-15"

  7. Set PCIe_SLOT based on your design example link width configuration. Modify the software flag below in the p0_software/user/common/include/ifc_libmqdma.h and p0_software/dpdk/dpdk/drivers/net/mcdma/rte_pmd_mcdma.h files.

    #define PCIe_SLOT 0 /* 0 - x16, 1 - x8, 2 – x4 */

    Example of software flag setting for x4 link width:

    #define PCIe_SLOT 2