Using the kernel function tracing system
Recent versions of the Linux kernel contain a set of tracers that, by instrumenting the kernel, allow you to analyze different areas like:
- Interrupt latency
- Preemption latency
- Scheduling latency
- Process context switches
- Event tracing
- Syscalls
- Maximum stack
- Block layer
- Functions
The tracers have no performance overhead when not enabled.
Getting ready...
The tracing system can be used in a wide variety of debugging scenarios, but one of the most common tracers used is the function tracer. It instruments every kernel function with a NOP call that is replaced and used to trace the kernel functions when a trace point is enabled.
To enable the function tracer in the kernel, use the CONFIG_FUNCTION_TRACER and CONFIG_FUNCTION_GRAPH_TRACER ...
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