Thread: Thoughts on OpenMP

I know some pretty heavy number crunching companies use OpenMP, so I guess it can't be "horrible".

Like all multithreading, you need to get fairly large independent chunks of data to calculate in each thread - then the overhead of the mechanisms to present the work becomes less of an issue. If you have small chunks of work, no form of multithreading is really that efficient.

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Mats

There's nothing wrong with it. It can pretty convenient. You could split a for loop into X threads very easily. I've only used it once, though, so I can't exactly say I'm an expert.
So look forward to someone else's advice too.

It's very terse. Compare the code overhead for making a computation loop multi-threaded with OpenMP - one line, I think, perhaps two or three - with the overhead from doing it by hand - something on the order of a dozen lines or two, if you consider the final joining. And that doesn't consider that the OpenMP implementation probably has a thread pool for the computation, and a message dispatching mechanism to use it. If you have to implement this yourself, it will be a lot more than just two dozen lines.
The job object API probably is a good alternative - I wouldn't be surprised if MS's OpenMP implementation used it internally.