It is the most detailed description of what an exokernel is and has the most recent numbers. It is also rather dense. This is a flamy paper describing the philosophical underpinnings of the exokernel approach. The following papers discuss three dynamic code generation systems. This paper appeared in PLDI '96.
Slides are available here .
It generates code in approximately 10 instructions per generated instruction, and is easily extendable by clients. A tutorial describing it can be obtained by clicking here . A beta version of the system is also available . Click here for a bit more information. This paper appeared in POPL 1996.