Hugepages Setup

Intel® Ethernet Controller E810 Data Plane Development Kit (DPDK) 22.11/23.03

Configuration Guide

ID	Date	Version	Classification
764257	06/16/2023	22.11	Public

Hugepage support is required for the large memory pool allocation used for packet buffers. By using hugepage allocations, performance is increased since fewer pages are needed, and therefore less Translation Lookaside Buffers (TLBs, high speed translation caches), which reduce the time it takes to translate a virtual page address to a physical page address. Without hugepages, high TLB miss rates would occur with the standard 4K page size, slowing performance.

For 1 GB pages

It is not possible to reserve the hugepage memory after the system has booted. The size must be specified explicitly and can also be optionally set as the default hugepage size for the system.

The 1 GB hugepage option can be added in Grub along with IOMMU in kernel command line, as shown in High Performance of Small Packets on 100G NIC- Use 16 Bytes Rx Descriptor Size.

To reserve 4 GB of hugepage memory in the form of four 1 GB pages, the following options should be passed to the kernel:

default_hugepagesz=1G hugepagesz=1G hugepages=4

Once the hugepage memory is reserved, to make the memory available for DPDK use, execute the following:

mkdir /mnt/huge mount -t hugetlbfs nodev /mnt/huge

For 1 GB pages, the mount point can be made permanent across reboots, by adding the following line to the /etc/fstab file:

nodev /mnt/huge hugetlbfs pagesize=1GB 0 0 Note:There are multiple ways to create hugepages under RHEL 7.x, following is one example that shows the steps to create four pages of 1 GB:

Create a mounting point for huge pages with auto-mount. cd /mnt mkdir huge

Modify /etc/fstab to include: nodev /mnt/huge hugetlbfs pagesize=1GB 0 0

Modify and update grub to set up hugepages. # /etc/default/grub GRUB_CMDLINE_LINUX="default_hugepagesz=1G hugepagesz=1G hugepages=4"
For RHEL:
grub2-mkconfig -o /boot/grub/grub.cfg
For Ubuntu:
Update-grub

Reboot the system and check Huge Page allocation. # cat /proc/meminfo | grep HugePages_Total HugePages_Total: 4 # cat /proc/meminfo | grep Hugepagesize Hugepagesize: 1048576 kB

For 2 MB pages

Hugepages can be allocated after the system has booted. This is done by echoing the number of hugepages required to a nr_hugepages file in the /sys/devices/ directory.

For a single-node system, the command to use is as follows (assuming that 1024 pages are required):

echo 1024 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages mount -t hugetlbfs nodev /mnt/huge

On a NUMA machine, pages should be allocated explicitly on separate nodes:

mkdir -p /mnt/huge echo 1024 > /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages echo 1024 > /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages mount -t hugetlbfs nodev /mnt/huge