tracing: adding function timings to function profiler
If the function graph trace is enabled, the function profiler will
use it to take the timing of the functions.
cat /debug/tracing/trace_stat/functions
Function Hit Time
-------- --- ----
mwait_idle 127 183028.4 us
schedule 26 151997.7 us
__schedule 31 151975.1 us
sys_wait4 2 74080.53 us
do_wait 2 74077.80 us
sys_newlstat 138 39929.16 us
do_path_lookup 179 39845.79 us
vfs_lstat_fd 138 39761.97 us
user_path_at 153 39469.58 us
path_walk 179 39435.76 us
__link_path_walk 189 39143.73 us
[...]
Note the times are skewed due to the function graph tracer not taking
into account schedules.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index d7410bb..c66ca3b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -605,6 +605,8 @@
/* Standard output formatting function used for function return traces */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern enum print_line_t print_graph_function(struct trace_iterator *iter);
+extern enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
#ifdef CONFIG_DYNAMIC_FTRACE
/* TODO: make this variable */
@@ -636,7 +638,6 @@
return 1;
}
#endif /* CONFIG_DYNAMIC_FTRACE */
-
#else /* CONFIG_FUNCTION_GRAPH_TRACER */
static inline enum print_line_t
print_graph_function(struct trace_iterator *iter)
