ftrace

Trace a single system call

This generates a function graph trace of a specific function and its callees:

# function to trace
func=ksys_mount

cd /sys/kernel/debug/tracing/
echo 0 > tracing_on
echo function_graph > current_tracer
echo $func > set_graph_function
echo 1 > tracing_on
echo > trace

# do thing here

echo 0 > tracing_on
echo nop > current_tracer

# save trace
cp trace /tmp/trace.txt