Commit 32fb7ef6 authored by Steffen Maier's avatar Steffen Maier Committed by Jonathan Corbet
Browse files

Documentation: ftrace: clarify filters with dynamic ftrace and graph 



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: default avatarSteffen Maier <maier@linux.ibm.com>
Reviewed-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 1ba2211c

Documentation/trace/ftrace.rst

+6 −1
Original line number Diff line number Diff line
@@ -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: