doc: Added documentation for using CPU profiler.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>

2 files changed, 68 insertions, 0 deletions

diff --git a/doc/rados/operations/cpu-profiling.rst b/doc/rados/operations/cpu-profiling.rst
new file mode 100644
index 00000000000..e46c5cab594
--- /dev/null
+++ b/doc/rados/operations/cpu-profiling.rst
@@ -0,0 +1,67 @@
+===============
+ CPU Profiling
+===============
+
+If you built Ceph from source and compiled Ceph for use with `oprofile`_
+you can profile Ceph's CPU usage. See `Installing Oprofile`_ for details.
+
+
+Initializing oprofile
+=====================
+
+The first time you use ``oprofile`` you need to initialize it. Locate the
+``vmlinux`` image corresponding to the kernel you are now running. :: 
+
+	ls /boot
+	sudo opcontrol --init
+	sudo opcontrol --setup --vmlinux={path-to-image} --separate=library --callgraph=6
+
+
+Starting oprofile
+=================
+
+To start ``oprofile`` execute the following command:: 
+
+	opcontrol --start
+
+Once you start ``oprofile``, you may run some tests with Ceph. 
+
+
+Stopping oprofile
+=================
+
+To stop ``oprofile`` execute the following command:: 
+
+	opcontrol --stop
+	
+	
+Retrieving oprofile Results
+===========================
+
+To retrieve the top ``cmon`` results, execute the following command:: 
+
+	opreport -gal ./cmon | less	
+	
+
+To retrieve the top ``cmon`` results with call graphs attached, execute the
+following command:: 
+
+	opreport -cal ./cmon | less	
+	
+.. important:: After reviewing results, you should reset ``oprofile`` before
+   running it again. Resetting ``oprofile`` removes data from the session 
+   directory.
+
+
+Resetting oprofile
+==================
+
+To reset ``oprofile``, execute the following command:: 
+
+	sudo opcontrol --reset   
+   
+.. important:: You should reset ``oprofile`` after analyzing data so that 
+   you do not commingle results from different tests.
+
+.. _oprofile: http://oprofile.sourceforge.net/about/
+.. _Installing Oprofile: ../../../install/cpu-profiler
diff --git a/doc/rados/operations/index.rst b/doc/rados/operations/index.rst
index 8c08b62e8f1..5829eea257d 100644
--- a/doc/rados/operations/index.rst
+++ b/doc/rados/operations/index.rst
@@ -14,6 +14,7 @@ and, monitoring an operating cluster.
 	
 	operating
 	monitoring
+	cpu-profiling
 	troubleshooting
 	debug