The Solaris Dynamic Tracing (DTrace) facility is a comprehensive dynamic tracking facility that gives you a new level of observerability into the Solaris kernel and user processes. DTrace helps you understand your system by permitting you to dynamically instrument the OS kernel and user processes to record data that you specify at locations of interest, called, probes. Each probe can be associated with custom programs that are written in the new D programming language. All of DTrace's instrumentation is entirely dynamic and available for use on your production system. For more information, see the dtrace(1M) man page and the Solaris Dynamic Tracing Guide.