QNX is also realtime.

In order to provide realtime guarantees that cover small latencies, you need infrastructure that generates as few instructions as possible. (If you have lots of instructions you can hit targets of a hundreds of microseconds since you can just wait. Start inching toward nanoseconds, though, and the scheduler's own execution will get in the way unless it's crazy compact.)

The reason I mention this is that QNX runs on a variety of embedded devices (http://qnx.symmetry.com.au/ has an interesting list, universal remotes particularly jumped out at me) which are traditionally quite slow.

What's Rust like in terms of generating code that's consistently compact?