ceph/doc/rados/troubleshooting/cpu-profiling.rst

   1 ===============
   2  CPU Profiling
   3 ===============
   4
   5 If you built Ceph from source and compiled Ceph for use with `oprofile`_
   6 you can profile Ceph's CPU usage. See `Installing Oprofile`_ for details.
   7
   8
   9 Initializing oprofile
  10 =====================
  11
  12 The first time you use ``oprofile`` you need to initialize it. Locate the
  13 ``vmlinux`` image corresponding to the kernel you are now running. ::
  14
  15         ls /boot
  16         sudo opcontrol --init
  17         sudo opcontrol --setup --vmlinux={path-to-image} --separate=library --callgraph=6
  18
  19
  20 Starting oprofile
  21 =================
  22
  23 To start ``oprofile`` execute the following command::
  24
  25         opcontrol --start
  26
  27 Once you start ``oprofile``, you may run some tests with Ceph.
  28
  29
  30 Stopping oprofile
  31 =================
  32
  33 To stop ``oprofile`` execute the following command::
  34
  35         opcontrol --stop
  36
  37
  38 Retrieving oprofile Results
  39 ===========================
  40
  41 To retrieve the top ``cmon`` results, execute the following command::
  42
  43         opreport -gal ./cmon | less
  44
  45
  46 To retrieve the top ``cmon`` results with call graphs attached, execute the
  47 following command::
  48
  49         opreport -cal ./cmon | less
  50
  51 .. important:: After reviewing results, you should reset ``oprofile`` before
  52    running it again. Resetting ``oprofile`` removes data from the session
  53    directory.
  54
  55
  56 Resetting oprofile
  57 ==================
  58
  59 To reset ``oprofile``, execute the following command::
  60
  61         sudo opcontrol --reset
  62
  63 .. important:: You should reset ``oprofile`` after analyzing data so that
  64    you do not commingle results from different tests.
  65
  66 .. _oprofile: http://oprofile.sourceforge.net/about/
  67 .. _Installing Oprofile: ../../../dev/cpu-profiler