Testsuite uses too many processes

[kanigsson]

The RecordFlux testsuite runs too many processes at the same time currently, this is probably because of the new support for multiprocessing #625. My suspicion is that the test driver runs n processes in parallel, which then each attempt to use n cores at the same time, where n is the number of available cores.

A possible solution is to add a configuration option to RecordFlux to control the number of processes to be used in parallel, and set it to 1 when run in the testsuite. The testsuite driver would continue to run n processes in parallel.

One could also do it the other way around, but usually there are many small tests that don't benefit from parallelism, so it seems the better tradeoff.

[senier]

A possible solution is to add a configuration option to RecordFlux to control the number of processes to be used in parallel, and set it to 1 when run in the testsuite. The testsuite driver would continue to run n processes in parallel.

That's how I've done it. Parallelism can now be configured in the constructor of the Message class, which as a default value of 1. In the CLI this value is configured to the number of available cores while the default is used in the tests (which themselves are parallelized). @kanigsson Please try whether the issue_755 branch fixes the issue on your system.

[kanigsson]

Yes, CPU load is back to normal with this patch.