acceleration.md

Hardware Acceleration

Ops can utilize your CPU's virtualization extension through the various supported hypervisors. Ops will only attempt to enable acceleration on systems that support it.

If you deploy to Google Cloud or AWS hardware acceleration will always be enabled however if you are developing locally you'll typically need to turn it on manually.

Also bear in mind that currently the VDSO is tied to pvclock and that requires hardware acceleration so you'll get another speed boost from that as well.

Linux

To have Ops enable hardware acceleration when running an image, first check to see if your system's chip has the appropriate support. An easy way to do this on modern Linux based systems is to run the following command:

$ grep -woE 'svm|vmx' /proc/cpuinfo | uniq

If you have a supported Intel CPU you should see the output vmx, for supported AMD processors you should see svm. If your CPU does not support a virtualization extension you will see no output. If you are certain that your CPU provides virtualization support and yet you see no output, then please ensure that the extension is enabled in your BIOS/UEFI system.

If using KVM you need to ensure that your user is a member of the kvm group. Ops will not attempt to enable acceleration if your user is not a member of this group. First check if your user is apart of the kvm group:

$ groups

If your user is a member of the group you should see kvm in the list. If not already a member you can add yourself to the group with the following command:

$ usermod -aG kvm `whoami`

The change will take effect upon the next login.

You can then verify by issuing the groups command ensuring you are in the kvm group:

$ groups

Finally, you can check to see if Ops is using virtualization support by inspecting the command it uses to run an image. You can do this by enabling verbose output when using the run or load commands. So assuming I have hardware acceleration enabled in my runtime configuration:

{
    "RunConfig": {
        "Accel": true
    }
}

Then the following command should indicate that hardware acceleration is being used:

$ ops run -v hello -c config.json
...
qemu-system-x86_64 -drive file=${HOME}/.ops/images/hello.img,format=raw,if=virtio -device virtio-net,netdev=n0 -netdev user,id=n0 -enable-kvm -nodefaults -no-reboot -device isa-debug-exit -m 2G -display none -serial stdio
...

Notice that the Qemu command is generated with -enable-kvm option.

Accelaration support can also be enabled by providing the --accel(-x) flag to the ops run or load commands.

$ ops run --accel hello  # or ops run -x hello

macOS

For macOS users things are a bit simpler. To check for virtualization support you can use the sysctl(8) command with the argument kern.hv_support:

$ sysctl kern.hv_support

The output will be kern.hv_support: 1 if support is enabled and kern.hv_support: 0 otherwise. Nothing more is needed on macOS, if hardware support is enabled in your runtime configuration then Ops generated hypervisor commands should include the appropriate acceleration options.