Here&#x27;s a good (introductory) resource on implementing green threads: <a href="http:&#x2F;&#x2F;c9x.me&#x2F;art&#x2F;gthreads&#x2F;intro.html" rel="nofollow">http:&#x2F;&#x2F;c9x.me&#x2F;art&#x2F;gthreads&#x2F;intro.html</a>. It&#x27;s helpful for learning how they work in practice.<p>Are people running into performance issues with green threads in practice? It seems like they&#x27;re already pretty performant, particularly if you&#x27;re using them more as an abstraction for concurrency than as a way to get parallelism. There are lots of problems that are trivial to solve with green threads&#x2F;coroutines but that are very difficult without them. If you really care about performance you probably shouldn&#x27;t be using green threads at all but should instead be running separate processes on dedicated cores. Green threads also have the advantage over kernel threads in that they don&#x27;t require the overhead of a kernel context switch, since the context switch can be done in userspace, which requires saving much less context and also affects your caches less.