Use fork_join_executor by default

[K-ballo]

No description provided.

[hkaiser]

LGTM, thanks!

[K-ballo]

The mere construction of a fork-join executor prevents other executors from making progress.

[hkaiser]

The mere construction of a fork-join executor prevents other executors from making progress.

Yes, that's a 'feature' and not a bug ;-)

[K-ballo]

The mere construction of a fork-join executor prevents other executors from making progress.

Yes, that's a 'feature' and not a bug ;-)

In that case any choice of executor should be removed entirely from the backend, as it will always lead to incorrect programs.

[hkaiser]

The mere construction of a fork-join executor prevents other executors from making progress.

Yes, that's a 'feature' and not a bug ;-)

In that case any choice of executor should be removed entirely from the backend, as it will always lead to incorrect programs.

If there is a way to customize the executor in the benchmark without adding it to the backend itself - sure, I'd agree.

[K-ballo]

This PR makes the fork_join_executor the default executor, not the only possible executor. When explicit policies are used, execution happens on the executor specified by the policy. Those executions can never progress since a fork_join_executor has been constructed. That's the reason this PR is still a draft: it does not work.

For things to work, the fork_join_executor has to be the only executor in the system.

If there is a way to customize the executor in the benchmark without adding it to the backend itself - sure, I'd agree.

I'm not aware of such a way.