Green threads, certainly, are far more lightweight than OS threads. But what I was saying is that the difference in weight between OS threads and processes has to do with shared vs. separate memory. If you want memory safety, you have to pay the price for it.

In addition, pipelines are much cheaper than forked workers that try to do the whole job.

On Sun, May 2, 2021 at 12:16 AM Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:

On Sat, May 1, 2021 at 8:51 PM John Cowan <xxxxxx@ccil.org> wrote:
They're not all that heavyweight, especially compared to Windows. But what makes processes heavier than OS threads is precisely swapping out memory maps.

Windows is a low bar in that regard. But I remember old-timers when I was in college laughing about how heavy Unix processes were.

In any case, the value of being able to use tens or hundreds of thousands of lightweight threads shouldn't be underestimated. Erlang and now Go get a lot of power from this idea.