CI: Enable GitHub Actions App for ppc64le (Power architecture) support

[sandeepgupta12]

Hi cryptography team,

We’ve successfully tested CI workflow changes for the ppc64le (Power) architecture using GitHub Actions (GHA) service provided by IBM. You can see an example run here:
🔗 CI run example
📌 Related NumPy tracking issue: numpy/numpy#29125

We’d now like to propose enabling the GitHub Actions app in this repository to allow running CI jobs for ppc64le directly via GitHub Actions. This would support upstream compatibility and help ensure continued support for the Power architecture in cryptography.

A few key details about the setup:

✅ Ephemeral and secure runners, isolated per job

🛠️ Maintained by IBM, integrated with GitHub’s standard GHA workflows

📚 Technical documentation: https://github.com/IBM/actionspz/tree/main/docs

We’re happy to assist with the setup or provide any additional details the team may need.

Thanks so much!

[alex]

This is something we'd definitely be potentially interested in.

Can you show us:

a) What a PR to any repo to add the configuration looks like?
b) How many concurrent builds can we do?
c) What sort of performance we can expect?
d) How are the images maintained -- do they match upstream GHA images?

[reaperhulk]

I see in your issue tracker that one of your criteria for projects that are getting onboarded is knowing a bit about load. If we choose to integrate this we'll be running it in our standard CI as well as our wheel builder since we do not produce wheels for untested architectures. So far this month we've run the CI workflow ~180 times and the wheel builder ~20 times, so you could expect us to run somewhere around 10-20 jobs per day on average (with heavy spikes occasionally during active development windows).