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::