=============== 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

oprofile must be initalized the first time it is used. Locate the vmlinux image that corresponds to the kernel you are running:

.. prompt:: bash $

ls /boot sudo opcontrol --init sudo opcontrol --setup --vmlinux={path-to-image} --separate=library --callgraph=6

Starting oprofile

Run the following command to start oprofile:

.. prompt:: bash $

opcontrol --start

Stopping oprofile

Run the following command to stop oprofile:

.. prompt:: bash $

opcontrol --stop

Retrieving oprofile Results

Run the following command to retrieve the top cmon results:

.. prompt:: bash $

opreport -gal ./cmon | less

Run the following command to retrieve the top cmon results, with call graphs attached:

.. prompt:: bash $

opreport -cal ./cmon | less

.. important:: After you have reviewed the results, reset oprofile before running it again. The act of resetting oprofile removes data from the session directory.

Resetting oprofile

Run the following command to reset oprofile:

.. prompt:: bash $

sudo opcontrol --reset

.. important:: Reset oprofile after analyzing data. This ensures that results from prior tests do not get mixed in with the results of the current test.

.. _oprofile: http://oprofile.sourceforge.net/about/ .. _Installing Oprofile: ../../../dev/cpu-profiler