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 <ma...@linux.ibm.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: Jonathan Corbet <cor...@lwn.net>
Cc: linux-doc@vger.kernel.org
 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..68835d062344 100644
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -224,6 +224,7 @@ 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 both the tracers "function" and "function_graph"!
        The functions listed in "available_filter_functions" are what
        can be written into this file.
@@ -265,6 +266,9 @@ 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).
+       With dynamic ftrace, the graph tracer can only trace functions that
+       set_ftrace_filter minus set_ftrace_notrace armed; this also influences
+       the ability to chase function call chains.
@@ -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.)

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

Reply via email to