How can I verify lock-free algorithms?

Question

In theory, it should be possible to at least brute force a verification of a lock-free algorithm (there are only so many combinations of function calls intersecting). Are there

Answer 1

I don't know what platform or language you're using - but on the .Net platform there is a Microsoft Research project called Chess which is looking very promising at helping those of us doing multithreaded components - including lock-free.

I've not used it a huge amount, mind.

It works (crude explanation) by explicitly interleaving threads in the tightest possible ways to actually force your bugs out into the wild. It also analyses code to find common mistakes and bad patterns - similar to code analysis.

In the past, I've also built special versions of the code in question (through #if blocks etc) that add extra state-tracking information; counts, versions etc that I can then dip into within a unit test.

The problem with that is that it takes a lot more time to write your code, and you can't always add this kind of stuff without changing the underlying structure of the code that's already there.