Use 64K page kernel on ARM64 instances

ARM64 platforms

Google Cloud currently provides two different CPU platforms for ARM64: Ampere Altra (via the “Tau” T2A machine type) and Google’s own Axion (via the N4A and C4A machine types).

64K page kernels

From Ubuntu 22.04 LTS onwards, two kernel variants are available to run ARM64: linux-gcp and linux-gcp-64k. “Standard” Ubuntu images on Google Cloud come preinstalled with the default linux-gcp kernel (see rmadison linux-gcp for details) but the “accelerator” Ubuntu image line comes with linux-gcp-64k. To see the latest accelerator-based images available, use:

gcloud compute images list --project=ubuntu-os-accelerator-images --no-standard-images

Note

The linux-gcp kernel will work on both CPU platforms, but linux-gcp-64k will not work on T2A machine types.

Changing the installed kernel

Should you wish to swap from the default kernel to the 64K page variant (or vice versa), run:

sudo apt update
sudo apt install linux-gcp-64k

After installation a pop-up courtesy of needrestart will appear recommending you to reboot. You must reboot the instance for the kernel to properly install:

sudo reboot

When you log back into the instance, to confirm the new kernel has indeed installed, run:

uname -r

More information

For more information about the different kernel variants and their use cases, refer to

• Choosing between 4K and 64K kernel options for ARM64

• Kernels on the cloud