Final answer:
The facility that dynamically adds probes to a running system is DTrace. DTrace is a dynamic tracing framework that allows users to instrument and analyze software running in real-time.
Step-by-step explanation:
The facility that dynamically adds probes to a running system, both in user processes and in the kernel, is DTrace. DTrace is a dynamic tracing framework that allows users to instrument and analyze software running in real-time.
DTrace provides a way to dynamically add probes, which are hooks into the system's code, allowing you to collect information about the system's behavior while it is running. These probes can be added to user processes as well as to the kernel.
For example, with DTrace, you can add probes to monitor the performance of a specific function in a user process or to track system calls in the kernel. This capability makes DTrace a powerful tool for debugging, performance analysis, and system monitoring.