[PATCH v2] Documentation: ftrace: clarify filters with dynamic ftrace and graph

[Steffen Maier <maier@linux.ibm.com>]

I fell into the trap of having set up function tracer with a very
limited filter and then switched over to function_graph and was
erroneously wondering why the latter did not trace what I expected,
which was the full unabridged graph recursion.

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---

Changes since v1:
Integrated review comments by Steven Rostedt
* less emotional phrasing
* also mention function profiling with set_ftrace_filter
  (hopefully I got that right as I don't have experience with it)

 Documentation/trace/ftrace.rst | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index e45f0786f3f9..9bbd3aefadb2 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -224,6 +224,8 @@ of ftrace. Here is a list of some of the key files:
 	has a side effect of enabling or disabling specific functions
 	to be traced. Echoing names of functions into this file
 	will limit the trace to only those functions.
+	This influences the tracers "function" and "function_graph"
+	and thus also function profiling (see "function_profile_enabled").
 
 	The functions listed in "available_filter_functions" are what
 	can be written into this file.
@@ -265,6 +267,8 @@ of ftrace. Here is a list of some of the key files:
 	Functions listed in this file will cause the function graph
 	tracer to only trace these functions and the functions that
 	they call. (See the section "dynamic ftrace" for more details).
+	Note, set_ftrace_filter and set_ftrace_notrace still affects
+	what functions are being traced.
 
   set_graph_notrace:
 
@@ -277,7 +281,8 @@ of ftrace. Here is a list of some of the key files:
 
 	This lists the functions that ftrace has processed and can trace.
 	These are the function names that you can pass to
-	"set_ftrace_filter" or "set_ftrace_notrace".
+	"set_ftrace_filter", "set_ftrace_notrace",
+	"set_graph_function", or "set_graph_notrace".
 	(See the section "dynamic ftrace" below for more details.)
 
   dyn_ftrace_total_info:
-- 
2.13.5

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html