This paper describes an interesting technology that Sun had been working on for quite some time and is now in production. The technology allows an IT admin to do deep performance analysis on parts of the system without having to instrument the system before hand (or unbundling it afterwards). What is also really really interesting, is that the system can be built for this without impacting performance. They call this the “zero probe effect” and it can be applied to the running kernel or the user-land applications. Very cool! Read the paper for the details, but essentially it is clever binary instrumentation.
http://www.sun.com/bigadmin/content/dtrace/dtrace_usenix.pdf
It’s interesting to see Sun finally attempt to compete with other kernels given their slow reaction over the past 6 years. This isn’t something you can just slap into a kernel.
Another interesting thought is what the implications of this are. When you have tools to work with finished code, neat things can be done.