Didn't I just say that "the problem with fork isn't really that it's slow"? It's all the other OS design choices it forces on you if you want it to be fast.
replyRight, you did. I somehow misread your comment.
replyWe don't have any broadly used non-fork samples. Windows, macOS, and Linux all have fork. So the presence of fork can't be the reason for the performance difference.
reply(Windows's fork is called ZwCreateProcess)
MacOS has posix_spawn. See https://developer.apple.com/library/archive/documentation/Sy... (yes, that’s an iOS man page. MacOS has the call, too, but I couldn’t find the man page online and it looks identical to me)
replyI don’t know how they implemented it, though. Under the hood, it could do the equivalent of a fork/exec pair.
XNU's posix_spawn implementation is not fork/exec-based. It does roughly what the API suggests it would do.
replyNtCreateProcess does not implement a forking model. It is analogous to posix_spawn.
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