Steven Rostedt, Open Source Programmer at VMware, maintains the Real Time Stable releases of the Linux kernel, among other things. Rostedt is one of the original developers of the PREEMPT_RT patch and began working on it in 2004 with the goal of turning Linux into a real-time designed operating system. He is also the main author, developer, and maintainer of Ftrace, a tool designed to help developers find what is going on inside the kernel. According to the Ftrace wiki, the tool can be used for debugging or analyzing latencies and performance issues that take place outside of user-space.