posix-spawn: a faster fork+exec for ruby

This is awesome, Aman's one of my favorite rubyists, I can't say I'm surprised to find out he's behind this.<p>If anyone's curious how processes/threads are represented internally on modern linux kernels, I wrote an article on that here: <a href="http://blog.andrewvc.com/fork2-is-dead-long-live-fork-i-mean-clone2" rel="nofollow">http://blog.andrewvc.com/fork2-is-dead-long-live-fork-i-mean...</a>

Wow, check out the Linux vs OSX graphs. Anyone care to enlighten me as to why they are <i>that</i> different? The worst OSX fork + exec call is more than 2x faster than the fastest fork + exec on Linux, and over 10x faster when the memory increases past ~300MB.<p>Given that OSX's isn't dependent on page table size, I'm guessing it just always does copy-on-write... but that's a pretty un-knowledgeable guess.

I'm curious what the applications are where this is an important optimization. Even for the very large Linux processes, it looks like 1/10sec per fork. On OSX, we're talking milliseconds. What sort of application is forking so often that this matters?

Here's the full announcement: <a href="https://gist.github.com/e0d36c881e6efc57514b" rel="nofollow">https://gist.github.com/e0d36c881e6efc57514b</a>