Build Executor is creating an excessive amount of threads

[Sanne]

This attempts to limit the build executor to a size dependent on the system, with a rough attempt at ergonomics.
More importantly, it allows setting system properties in the build to fully control the sizes, allowing further experimentation.

Fixes #49574

[dmlloyd]

I have no idea if the sizes are right. But the code looks OK.

[geoand]

Do we have any examples showing what the behavior of a Quarkus build is pre and post this change?

[gsmet]

@geoand so we might debate on the factor to number of cores but starting up to 1024 threads regardless of the number of cores seems excessive to me and I think Sanne's approach makes sense.

Now I could try to check with different values if we can agree we want to limit the number of threads.

[Sanne]

Applied one more suggestion by @gsmet and rebased - let's merge it (if it's green)

[quarkus-bot]

Status for workflow Quarkus CI

This is the status report for running Quarkus CI on commit b9c907e.

✅ The latest workflow run for the pull request has completed successfully.

It should be safe to merge provided you have a look at the other checks in the summary.

You can consult the Develocity build scans.

[Sanne]

I need a review approval please :)