This blog post is one of those things that just blew up. From a tiny observation at work about odd behaviors of spinlocks I spent months trying to find good benchmarks, (still not entirely successful) writing my own spinlocks, mutexes and condition variables and even contributing a patch to the Linux kernel. The main thing I’ll try to answer is to give some more informed guidance on the endless discussion of mutex vs spinlock. Besides that I found that most mutex implementations are really good, that most spinlock implementations are pretty bad, and that the Linux scheduler is OK but far from ideal. The most popular replacement, the MuQSS scheduler has other problems instead. (the Windows scheduler is pretty good though)