Offloading works if all vms on same bridge use offloading

[nirs]

In docs/usage.md we warn about offloading inconsistent performance, but since macOS 26.2 it works great - we get near native performance.
See details in nirs/vmnet-helper#176

[jakecorrenti]

Feel like opening a PR @nirs?

[nirs]

@jakecorrenti I want to do more testing.

[nirs]

@jakecorrenti When libkrun/libkrun#556 is merged and released, we need to create a krunkit release. Then we can make offloading the recommended way on macOS 26.2 or alter.

Need also to document that for best results vms communicating with each other should have the same offloading options. Performance is inconsistent and horrible otherwise.

Good configurations:

• vfkit <-> krunkit (offloading=off)
• krunkit (offloading=off) <-> krunkit (offloading=off)

Bad configurations:

• vfkit <-> krunkit (offloading=on)
• krunkit (offloading=off) <-> krunkit (offloading=on)

[nirs]

@jakecorrenti I did more testing with minikube clusters with mixed results:

• Great performance when using host network - up to 5x times faster than vfkit
• Completely broken when iperf client and server are in the pod network
  So offloading cannot be the default for minikube, but it can an option.

For more details see https://github.com/nirs/vmnet-helper/blob/minikube/performance/2026-02/M2/minikube/report.md

I need to complete the test matrix:

• krunkit without offloading (what minikube uses now)
• client on vfkit vm, server on krunkit vm with/without offloading (tested manually)

[jakecorrenti]

Thanks @nirs! keeping an eye on the libkrun PR

[nirs]

@jakecorrenti libkrun/libkrun#556 is merged, but not released yet.

When libkrun with this fix is merged, we can recommend using offloading for the specific cases that work, and warn about the case that not work.

This is documented now in vmnet-helper:
https://github.com/nirs/vmnet-helper/blob/main/docs/performance.md#offloading

[jakecorrenti]

Thanks @nirs, we still don't have the libkrun release done yet but I we can follow up the release with some docs changes

[nirs]

@slp said in the matrix channel that we should have a release next week. I don't have new info on negative tests except the minikube branch I shared before.

For positive cases, see the current offloading docs in vmnet-helper I shared in #90 (comment)

[nirs]

@jakecorrenti Turns out that this is not related to macOS 26.2. The issue is mixing vms with different offloading options on the same bridge:
nohajc/anylinuxfs#127 (comment)

So it should work on macOS 15, and it can break on macOS 26. Minikube added an option to enable offloading for brave users:
kubernetes/minikube#22962

Lastet benchmark results:
https://github.com/nirs/vmnet-helper/blob/main/docs/podman.md#results