Ensure that thread-shared variable is initialized by single thread

[heplesser]

This PR ensures that the thread-global variable decrease_buffer_size_spike_data_ is initialized by a single thread before entering the region in which it is used.

[jougs]

@heplesser: I am generally positive towards the changes, but can you please provide a description of the problem this is solving or a link to an issue?

[heplesser]

@heplesser: I am generally positive towards the changes, but can you please provide a description of the problem this is solving or a link to an issue?

I have added a short description and merged master so the actual change becomes better visible.

[jougs]

Thanks!

[github-actions]

Pull request automatically marked stale!

[suku248]

Thanks @heplesser !

Just for the record: This is one of the suspicious lines of code we checked during one of our Hackathons?
And we concluded that:

• not having this in a single environment did not result in erroneous behavior, but it has the potential to cause errors in thread-parallel code, and
• runtime measurements showed that the single environment does have an effect on the runtime?

[heplesser]

Just for the record: This is one of the suspicious lines of code we checked during one of our Hackathons? And we concluded that:

• not having this in a single environment did not result in erroneous behavior, but it has the potential to cause errors in thread-parallel code, and
• runtime measurements showed that the single environment does have an effect on the runtime?

Yes to all!