12. Kernel
The operating system kernel is the software at the heart of a system, managing system resources and user processes. It has historically been difficult to observe as it executes in a protected context, beyond the reach of process debuggers. DTrace provides custom visibility into kernel operations, allowing you to answer questions such as the following.
• Where is the kernel spending time consuming CPU cycles?
• What kernel memory allocations are occurring, and for which segments?
• When are functions executing? And with what arguments?
• Why are functions being executed? What is their stack backtrace?
• How long does it take to execute kernel functions? On-cpu/off-cpu?
As an example, the following one-liner traces all kernel function ...
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