2M Hugepages

DPDK apps generally need hugepages support, for tyre-kicking purposes this should be enough to get it going, Fedora and RHEL default to 2M hugepages:

# sysctl -w vm.nr_hugepages=512

For real-world applications you’d want to make such an allocation permanent. You can do this by adding it to /etc/sysctl.conf or a separate file in the /etc/sysctl.d/ directory.:

# echo 'vm.nr_hugepages=512' > /etc/sysctl.d/hugepages.conf

1G Hugepages

Many applications require 1GB hugepages to be used though, and the others might perform better with them. 1GB hugepages must be allocated at boot time via kernel command line. For example to allocate four 1GB hugepages, you should append this to the kernel commandline when booting:

default_hugepagesz=1GB hugepagesz=1G hugepages=4

To permanently add this to the kernel commandline, append it to GRUB_CMDLINE_LINUX in /etc/default/grub and then execute:

# grub2-mkconfig -o /boot/grub2/grub.cfg

Reboot to make sure it worked. If your system is correctly configured for hugepage support, you should be able to execute the following command and see non-zero values, corresponding to your hugepage configuration:

# grep HugePages_ /proc/meminfo

NOTE Most x86_64 systems support various sizes of hugepages. It is possible for your system not to have 1GB support. Check by running the following:

# if grep pdpe1gb /proc/cpuinfo >/dev/null 2>&1; then echo "1GB supported."; fi