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 ``oprofile`` must be initalized the first time it is used. Locate the
  13 ``vmlinux`` image that corresponds to the kernel you are running:
  14
  15 .. prompt:: bash $
  16
  17    ls /boot
  18    sudo opcontrol --init
  19    sudo opcontrol --setup --vmlinux={path-to-image} --separate=library --callgraph=6
  20
  21
  22 Starting oprofile
  23 =================
  24
  25 Run the following command to start ``oprofile``:
  26
  27 .. prompt:: bash $
  28
  29    opcontrol --start
  30
  31
  32 Stopping oprofile
  33 =================
  34
  35 Run the following command to stop ``oprofile``:
  36
  37 .. prompt:: bash $
  38
  39    opcontrol --stop
  40
  41
  42 Retrieving oprofile Results
  43 ===========================
  44
  45 Run the following command to retrieve the top ``cmon`` results:
  46
  47 .. prompt:: bash $
  48
  49    opreport -gal ./cmon | less
  50
  51
  52 Run the following command to retrieve the top ``cmon`` results, with call
  53 graphs attached:
  54
  55 .. prompt:: bash $
  56
  57    opreport -cal ./cmon | less
  58
  59 .. important:: After you have reviewed the results, reset ``oprofile`` before
  60    running it again. The act of resetting ``oprofile`` removes data from the
  61    session directory.
  62
  63
  64 Resetting oprofile
  65 ==================
  66
  67 Run the following command to reset ``oprofile``:
  68
  69 .. prompt:: bash $
  70
  71    sudo opcontrol --reset
  72
  73 .. important:: Reset ``oprofile`` after analyzing data. This ensures that
  74    results from prior tests do not get mixed in with the results of the current
  75    test.
  76
  77 .. _oprofile: http://oprofile.sourceforge.net/about/
  78 .. _Installing Oprofile: ../../../dev/cpu-profiler
  79
  80