Linux Kernel Developer: Steven Rostedt

Linus Torvalds recently released version 4.16 of the Linux kernel. These releases typically occur every nine to ten weeks, and each one contains the work of more than 1,600 developers representing over 200 corporations, according to the 2017 Linux Kernel Development Report, written by Jonathan Corbet and Greg Kroah-Hartman. In this series, we’re highlighting some of the developers who contribute to the kernel.

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.

Additionally, this past year, Rostedt found time to speak at various events and serve on The Linux Foundation’s technical advisory board. Here are Rostedt’s responses to our questions.

Linux Foundation: What role do you play in the community and what subsystem(s) do you work on?

Steven Rostedt: I partake in a lot of the Linux Foundation events as well as Kernel Recipes, Linux Plumbers, sometimes Linux Tag and other events. I’m on The Linux Foundation’s Technical Advisory Board (TAB) and was on the Linux Plumbers programming committee. I’m an Open Source advocate and try to communicate to people what that means. I maintain the Real Time Stable releases, and the Ftrace (Linux kernel tracer) subsystem, as well as ktest, localmodconfig, and Ftrace tools like trace-cmd and KernelShark.

Linux Foundation: What have you been working on this year? / What’s one way you have contributed to the 4.8 to 4.13 releases?

Rostedt: I’ve been working on having ftrace trace init functions in both the main kernel core as well as in modules. Between 4.8 and 4.13, I rewrote the function tracing trigger code to be able to be expanded and used to enable function filtering for tracing on modules before they are loaded.

Linux Foundation:  What do you think the kernel community needs to work on in the upcoming year?

Rostedt: I think more focus should be on eBPF and helping it be easier to use as well as having an eye on security. Running a VM within the kernel can be very dangerous, and people need to use caution and be extra careful during development.

Linux Foundation: Why do you contribute to the Linux kernel?

Rostedt: Because it is the one place that you have total control over your computer.

At the recent Embedded Linux Conference, Rostedt presented a session on “Maintaining a Real Time Stable Kernel,” in which he explained what’s required to maintain a stable RT tree, which is a bit different from maintaining a normal stable tree. In this talk, he covered various tools that can be used and described the current tests performed to ensure that the RT stable kernel is fully functional.

You can learn more about the Linux kernel development process and read more developer profiles in the full report. Download the 2017 Linux Kernel Development Report now.