Unit testing concurrent software - what do you do?

Question

As software gets more and more concurrent, how do you handle testing the core behaviour of the type with your unit tests (not the parallel behaviour, just the core

Answer 1

A technique I've found useful is to run tests within a tool that detects race conditions like Intel Parallel Inspector. The test runs much slower than normal, because dependencies on timing have to be checked, but a single run can find bugs that otherwise would require millions of repeated ordinary runs.

I've found this very useful when converting existing systems for fine-grained parallelism via multi-core.