Documentation: tracing: boot: Add an example of tracing function-calls (19c311ae) · Commits · 戴 / test

Add an example of tracing function calls on a specific function. Link: https://lkml.kernel.org/r/159972816669.428528.12390560334549382316.stgit@devnote2 Signed-off-by:

Documentation/trace/boottime-trace.rst

+20 −0

Original line number	Diff line number	Diff line
		@@ -168,6 +168,26 @@ is for tracing functions starting with "user\_", and others tracing
		The instance node also accepts event nodes so that each instance
		can customize its event tracing.

		With the trigger action and kprobes, you can trace function-graph while
		a function is called. For example, this will trace all function calls in
		the pci_proc_init()::

		ftrace {
		tracing_on = 0
		tracer = function_graph
		event.kprobes {
		start_event {
		probes = "pci_proc_init"
		actions = "traceon"
		}
		end_event {
		probes = "pci_proc_init%return"
		actions = "traceoff"
		}
		}
		}


		This boot-time tracing also supports ftrace kernel parameters via boot
		config.
		For example, following kernel parameters::