Best practices to turn a .NET class library into a multithreaded .NET class library

Question

I have some C# class libraries, that were designed without taking into account things like concurrency, multiple threads, locks, etc...

The code is very well structured, it is easily expandable, but it can benefit a lot from multithreading: it's set of scientific/engineering libraries that need to perform billions of calculations in very-very short time (and now they don't take benefit from the available cores).

I want to transform all this code into a set of multithreaded libraries, but I don't know where to start and I don't have any previous experience.

I could use any available help, and any recommendations/suggestions.

Answer 1

My recommendation would be to not do it. You didn't write that code to be used in parallel, so it's not going to work, and it's going to fail in ways that will be difficult to debug.

Instead, I recommend you decide ahead of time which part of that code can benefit the most from parallelism, and then rewrite that code, from scratch, to be parallel. You can take advantage of having the unmodified code in front of you, and can also take advantage of existing automated tests.

It's possible that using the .NET 4.0 Task Parallel Library will make the job easier, but it's not going to completely bridge the gap between code that was not designed to be parallel and code that is.