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

To start oprofile execute the following command:

opcontrol --start

Once you start oprofile, you may run some tests with Ceph.

To stop oprofile execute the following command:

opcontrol --stop

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.

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.