cddl/contrib/dtracetoolkit/Examples/hotuser_example.txt

   1 The following are demonstrations of the hotuser DTrace program.
   2
   3
   4 Here, hotuser is run on a test program called "dofuncs", which is hard coded
   5 to spend half its time in delta(), a third in beta() and a sixth in alpha().
   6
   7    # ./hotuser -c ./dofuncs
   8    Sampling... Hit Ctrl-C to end.
   9    ^C
  10    FUNCTION                                                COUNT   PCNT
  11    dofuncs`alpha                                             511  16.5%
  12    dofuncs`beta                                             1029  33.3%
  13    dofuncs`delta                                            1552  50.2%
  14
  15 hotuser has accurately sampled which user-level functions are on the CPU,
  16 producing a report of the expected breakdown. The hottest user-level function
  17 is delta(), which was sampled 1552 times - 50.2% of the total samples.
  18
  19
  20
  21 Now hotuser is run on gunzip, to find which functions are most often
  22 on the CPU,
  23
  24    # ./hotuser -c 'gunzip contents.gz'
  25    Sampling... Hit Ctrl-C to end.
  26
  27    FUNCTION                                                COUNT   PCNT
  28    libc.so.1`_free_unlocked                                    1   0.1%
  29    gunzip`unzip                                                1   0.1%
  30    ld.so.1`strcmp                                              1   0.1%
  31    gunzip`inflate_dynamic                                      1   0.1%
  32    libc.so.1`_write                                            1   0.1%
  33    gunzip`write_buf                                            1   0.1%
  34    gunzip`0x2d990                                              2   0.3%
  35    libc.so.1`write                                             2   0.3%
  36    gunzip`0x2d994                                              2   0.3%
  37    ld.so.1`rtld_db_preinit                                     3   0.4%
  38    gunzip`0x2d98c                                              7   0.9%
  39    gunzip`huft_build                                           9   1.2%
  40    libc_psr.so.1`memcpy                                      138  18.5%
  41    gunzip`inflate_codes                                      233  31.2%
  42    gunzip`updcrc                                             344  46.1%
  43
  44 This shows that updcrc() was sampled 344 times, and 46.1% of the total
  45 samples.
  46
  47
  48
  49 A -l option will provide a breakdown on libraries only. hotuser
  50 is run on gzip to show library usage only,
  51
  52    # ./hotuser -lc 'gzip contents'
  53    Sampling... Hit Ctrl-C to end.
  54
  55    LIBRARY                                                 COUNT   PCNT
  56    libc.so.1                                                   2   0.0%
  57    libc_psr.so.1                                              37   0.9%
  58    gzip                                                     4113  99.1%
  59
  60 This shows that code in the gzip binary itself was on the CPU 99.1% of
  61 the sample times, with libc_psr.so.1 code on the CPU 0.9% of the time.
  62
  63
  64
  65 The following shows library usage of mozilla. The pgrep command is used to
  66 match the most recent PID of mozilla-bin.
  67
  68    # ./hotuser -lp `pgrep -n mozilla-bin`
  69    Sampling... Hit Ctrl-C to end.
  70    ^C
  71    LIBRARY                                                 COUNT   PCNT
  72    libplds4.so                                                 1   0.1%
  73    libappcomps.so                                              1   0.1%
  74    libi18n.so                                                  1   0.1%
  75    libuconv.so                                                 1   0.1%
  76    libpref.so                                                  1   0.1%
  77    libblueprint.so                                             1   0.1%
  78    libz.so.1                                                   2   0.2%
  79    libcaps.so                                                  2   0.2%
  80    libXrender.so.1                                             2   0.2%
  81    libimglib2.so                                               2   0.2%
  82    libXft.so.2                                                 3   0.3%
  83    libCrun.so.1                                                3   0.3%
  84    libdocshell.so                                              3   0.3%
  85    libplc4.so                                                  4   0.4%
  86    libgtk-x11-2.0.so.0.400.9                                   5   0.5%
  87    libjsd.so                                                   5   0.5%
  88    libX11.so.4                                                 5   0.5%
  89    libnecko.so                                                 8   0.9%
  90    libwidget_gtk2.so                                           9   1.0%
  91    libgkgfx.so                                                13   1.4%
  92    libglib-2.0.so.0.400.1                                     14   1.5%
  93    libgfx_gtk.so                                              18   2.0%
  94    libnspr4.so                                                20   2.2%
  95    libxpconnect.so                                            22   2.4%
  96    libgdk-x11-2.0.so.0.400.9                                  23   2.5%
  97    libgobject-2.0.so.0.400.1                                  25   2.7%
  98    libhtmlpars.so                                             27   3.0%
  99    libfontconfig.so.1                                         41   4.5%
 100    libxpcom.so                                                49   5.4%
 101    mozilla-bin                                                55   6.0%
 102    libmozjs.so                                                80   8.8%
 103    libc.so.1                                                 115  12.6%
 104    libgklayout.so                                            352  38.6%
 105
 106 This shows that 352 samples found code from libgklayout.so running, which
 107 was 38.6% of the samples.