Yes, I think you're right that UMCG is just for within a single process. It's meant to support Google's fibers library, which offers a nice structured concurren

Yes, I think you're right that UMCG is just for within a single process. It's meant to support Google's fibers library, which offers a nice structured concurrency programming model within a process with nested schedulers. Eg, the outermost scheduler might be earliest fiber tree gets scheduled first, and then within a fiber tree (which often represents one request) the scheduler is typically LIFO for efficiency. The idea is that when using this library, the process has more information about what its threads are doing, so it can make better scheduling decisions than the kernel and can do it more quickly. It doesn't replace the kernel scheduler exactly, just makes it have less to do because there are fewer unblocked threads per process. This ghOSt thing looks unrelated and system-wide. Like a more customizable version of the usual kernel scheduling. But I'm guessing based on one paragraph and will be interested to see the paper/presentation. I'm not sure if there's any big gap between where neither does what you want.