SystemTap!

strace is a diagnostic, debugging and instructional userspace utility for Linux. It is used to monitor interactions between processes and the Linux kernel, which include system calls, signal deliveries, and changes of process state. The operation of strace is made possible by the kernel feature known as ptrace.

DTrace is a performance analysis and troubleshooting tool that is included by default with various operating systems, including Solaris, Mac OS X and FreeBSD. A Linux port is in development.

ltrace intercepts and records dynamic library calls which are called by an executed process and the signals received by that process. It can also intercept and print the system calls executed by the program. Used for debugging.

Ftrace is an internal tracer designed to help out developers anddesigners of systems to find what is going on inside the kernel.It can be used for debugging or analyzing latencies andperformance issues that take place outside of user-space.

ktap is a script-based dynamic tracing tool for Linux. It uses a scripting language and lets users trace the Linux kernel dynamically. ktap is designed to give operational insights with interoperability that allows users to tune, troubleshoot and extend the kernel and applications. It's similar to Systemtap and DTrace.

The ktrace utility enables kernel trace logging for the specified processes. Kernel trace data is logged to the file ktrace.out. The kernel operations that are traced include system calls, namei translations, signal processing, and I/O.