[BenoitP]

> libc is pretty shallow. The majority are either leaf functions like strlen(), or <5 levels from a leaf/before execution disappears into a system call.)

I'd wager that the JIT in OP's picture will transform that huge call stack into something <5 levels from CPU instructions/syscalls.

What remains though, is the huge context carried around such a stack; and I'm quite excited at what the Loom project [1] could yield to tackle that.

Such huge call stacks are a good sign to me. I don't want to implement all the corner cases of all the RFC I rely on; and it is great that library implementors can organise their code well. In the end the JIT will adapt my program to the currently used corner case, and prune everything else.

[1] http://cr.openjdk.java.net/~rpressler/loom/Loom-Proposal.htm...