CI agent on Linux ARM64

[martin-g]

Hello,

I am new to the community and I am interested to run SU2 on Linux ARM64.

I've just noticed #1609 (issue) and #1610 (PR with a fix).

I see the project uses Github Actions as CI (https://github.com/su2code/SU2/pull/1610/checks).
Unfortunately Github Actions has only x86_64 build nodes in the cloud. Linux ARM64 is supported but only for self-hosted build nodes but those are not recommended for public repositories like this one.

What are the project's options to add CI on ARM64 ?
My employer could provide a VM for long term usage if there is an interest!

Regards,
Martin

[pcarruscag]

Hello, we can talk about this in more detail in today's developer meeting https://meet.jit.si/SU2_DevMeeting at 3pm UK (if you can join).

[martin-g]

Thanks for the invitation!
I will try to join !

[martin-g]

Hi @pcarruscag !

I thought a bit how to setup the ARM64 builder node and came with the following idea:

1. Setup a self-hosted runner
2. Duplicate https://github.com/su2code/SU2/blob/master/.github/workflows/regression.yml
3. Change the on part to be a scheduled run only on master branch.
4. Replace ubuntu-latest with the self-hosted runner in all runs-on

I.e. the ARM64 self-hosted runner will be used for post-validation only. It will execute only approved and merged code to master.
There are not that many commits per day, so the post-validation should be still useful. If needed it may be scheduled several times per day to shrink the time window and make it easier to pin point which merge caused a regression.

The only drawback I see is that we will have to duplicate the code in regression.yml. I see no way how to reuse it.

WDYT ?

[martin-g]

Hi Pedro!

I will work on this and send a PR soon!

Since we would be copying the script we could run just on merges into develop, and not on pull requests to reduce overhead.

What do you mean here ?
I have the feeling you suggest to remove this:

SU2/.github/workflows/regression.yml

Lines 8 to 11 in 42d1571

	pull_request:
	branches:
	- 'develop'
	- 'master'

I think the PR validation (on x86_64) would be still useful!

[pcarruscag]

Yes, but if you end up with a completely different script for ARM, then we may not need to run on every update of a pull request.
Maybe I got it wrong and you only want to duplicate part of the script inside itself?

[martin-g]

Let me try and see what kind of changes would be needed!

[martin-g]

How did you build https://hub.docker.com/r/su2code/build-su2 ?
At the moment it is linux/amd64 only.
Did you push it manually or it is automated somewhere ?

[pcarruscag]

Hi Martin, the docker scripts are here https://github.com/su2code/Docker-Builds