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authorRobert Elliott <elliott@hp.com>2014-05-20 17:10:51 -0500
committerSteven Rostedt <rostedt@goodmis.org>2014-05-20 23:29:32 -0400
commit607e3a29203633eaec7334f2f58f9653df788a06 (patch)
treef4fc79986cbd5cb935141e47a982f014c1aeadcc /Documentation/trace
parentccdb594653b1c0d5b0f3e6f8bf764c544ba0606d (diff)
downloadlinux-607e3a29203633eaec7334f2f58f9653df788a06.tar.bz2
tracing: Add funcgraph_tail option to print function name after closing braces
In the function-graph tracer, add a funcgraph_tail option to print the function name on all } lines, not just functions whose first line is no longer in the trace buffer. If a function calls other traced functions, its total time appears on its } line. This change allows grep to be used to determine the function for which the line corresponds. Update Documentation/trace/ftrace.txt to describe this new option. Link: http://lkml.kernel.org/p/20140520221041.8359.6782.stgit@beardog.cce.hp.com Signed-off-by: Robert Elliott <elliott@hp.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/ftrace.txt26
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index bd365988e8d8..2479b2a0c77c 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -2003,6 +2003,32 @@ want, depending on your needs.
360.774530 | 1) 0.594 us | __phys_addr();
+The function name is always displayed after the closing bracket
+for a function if the start of that function is not in the
+trace buffer.
+
+Display of the function name after the closing bracket may be
+enabled for functions whose start is in the trace buffer,
+allowing easier searching with grep for function durations.
+It is default disabled.
+
+ hide: echo nofuncgraph-tail > trace_options
+ show: echo funcgraph-tail > trace_options
+
+ Example with nofuncgraph-tail (default):
+ 0) | putname() {
+ 0) | kmem_cache_free() {
+ 0) 0.518 us | __phys_addr();
+ 0) 1.757 us | }
+ 0) 2.861 us | }
+
+ Example with funcgraph-tail:
+ 0) | putname() {
+ 0) | kmem_cache_free() {
+ 0) 0.518 us | __phys_addr();
+ 0) 1.757 us | } /* kmem_cache_free() */
+ 0) 2.861 us | } /* putname() */
+
You can put some comments on specific functions by using
trace_printk() For example, if you want to put a comment inside
the __might_sleep() function, you just have to include