cddl/contrib/dtracetoolkit/Examples/rfileio_example.txt

   1 The following are demonstrations of the rfileio.d script.
   2
   3
   4 rfileio.d prints file system statistics by file,
   5
   6    # ./rfileio.d
   7
   8    Read IOPS, top 20 (count)
   9    /lib/ld.so.1                                              logical          2
  10    /devices/pseudo/clone@0:ptm                               logical          4
  11    /usr/bin/grep                                             logical          4
  12    /devices/pseudo/pts@0:3                                   logical          4
  13    /extra1/contents                                         physical       1700
  14    /extra1/contents                                          logical      11582
  15
  16    Read Bandwidth, top 20 (bytes)
  17    /devices/pseudo/pts@0:3                                   logical          3
  18    /devices/pseudo/clone@0:ptm                               logical         92
  19    /lib/ld.so.1                                              logical        212
  20    /usr/bin/grep                                             logical        269
  21    /extra1/contents                                         physical   48115712
  22    /extra1/contents                                          logical   94865162
  23
  24    Total File System miss-rate: 50%
  25    ^C
  26
  27    $ ls -l /extra1/contents
  28    -rw-r--r--   1 root     root     94865162 Nov  2 21:08 /extra1/contents
  29
  30 The /extra1/contents file was read using the grep command. The output shows
  31 that half of the contents was returned from the cache, the other half from disk
  32 (50% miss-rate). It is 94,865,162 bytes in size, which can be seen both in
  33 the ls -l output and the logical read() bytes reported by rfileio.d. There
  34 were 11,582 logical read() calls, which the disk driver satisfied by using
  35 1,700 disk events (aggregation).
  36
  37
  38
  39 The following demonstrates many files being read.
  40
  41    # ./rfileio.d
  42
  43    Read IOPS, top 20 (count)
  44    /usr/bin/amd64/glib-mkenums                               logical          4
  45    /usr/bin/amd64/glib-genmarshal                           physical          4
  46    /usr/bin/amd64/gdk-pixbuf-query-loaders                   logical          4
  47    /usr/bin/amd64/ls                                         logical          5
  48    /usr/bin/amd64/pargs                                      logical          5
  49    /usr/bin/amd64/ps                                         logical          5
  50    /usr/bin/amd64/gconf-merge-tree                          physical          6
  51    /usr/bin/amd64/cputrack                                   logical          6
  52    /usr/bin/amd64/gconftool-2                               physical          6
  53    /usr/bin/amd64/prctl                                      logical          6
  54    /usr/bin/amd64/prstat                                     logical          6
  55    /usr/bin/amd64/glib-genmarshal                            logical          7
  56    /usr/bin/amd64/truss                                     physical          8
  57    /usr/bin/amd64/sort                                       logical          9
  58    /usr/bin/amd64/prex                                       logical         10
  59    /usr/bin/amd64/gconf-merge-tree                           logical         13
  60    /usr/bin/amd64/mdb                                       physical         15
  61    /usr/bin/amd64/gconftool-2                                logical         15
  62    /usr/bin/amd64/truss                                      logical         26
  63    /usr/bin/amd64/mdb                                        logical         63
  64
  65    Read Bandwidth, top 20 (bytes)
  66    /usr/bin/amd64/prctl                                      logical      36784
  67    /usr/bin/amd64/prctl                                     physical      36864
  68    /usr/bin/amd64/prstat                                     logical      44760
  69    /usr/bin/amd64/prstat                                    physical      45056
  70    /usr/bin/amd64/glib-genmarshal                            logical      46064
  71    /usr/bin/amd64/glib-genmarshal                           physical      46080
  72    /usr/bin/amd64/cputrack                                   logical      46912
  73    /usr/bin/amd64/cputrack                                  physical      47104
  74    /usr/bin/amd64/sort                                       logical      65120
  75    /usr/bin/amd64/sort                                      physical      65536
  76    /usr/bin/amd64/prex                                       logical      80968
  77    /usr/bin/amd64/prex                                      physical      81920
  78    /usr/bin/amd64/gconf-merge-tree                           logical     113592
  79    /usr/bin/amd64/gconf-merge-tree                          physical     122880
  80    /usr/bin/amd64/gconftool-2                                logical     129208
  81    /usr/bin/amd64/gconftool-2                               physical     139264
  82    /usr/bin/amd64/truss                                      logical     246360
  83    /usr/bin/amd64/truss                                     physical     262144
  84    /usr/bin/amd64/mdb                                        logical     627456
  85    /usr/bin/amd64/mdb                                       physical     638976
  86
  87    Total File System miss-rate: 81%
  88    ^C
  89
  90 The miss-rate was 81%, meaning we are returning around 20% of the data from
  91 the cache. Details for the top 20 files read by-bytes and by-count are listed;
  92 this shows the /usr/bin/amd64/mdb file was read() 63 times, causing 15 disk
  93 reads, and while 627,456 bytes were requested, 638,976 bytes were read from
  94 disk (the extra bytes are due to read-ahead and file system metadata).