rfileio_example.txt [plain text]
The following are demonstrations of the rfileio.d script.
rfileio.d prints file system statistics by file,
# ./rfileio.d
Read IOPS, top 20 (count)
/lib/ld.so.1 logical 2
/devices/pseudo/clone@0:ptm logical 4
/usr/bin/grep logical 4
/devices/pseudo/pts@0:3 logical 4
/extra1/contents physical 1700
/extra1/contents logical 11582
Read Bandwidth, top 20 (bytes)
/devices/pseudo/pts@0:3 logical 3
/devices/pseudo/clone@0:ptm logical 92
/lib/ld.so.1 logical 212
/usr/bin/grep logical 269
/extra1/contents physical 48115712
/extra1/contents logical 94865162
Total File System miss-rate: 50%
^C
$ ls -l /extra1/contents
-rw-r--r-- 1 root root 94865162 Nov 2 21:08 /extra1/contents
The /extra1/contents file was read using the grep command. The output shows
that half of the contents was returned from the cache, the other half from disk
(50% miss-rate). It is 94,865,162 bytes in size, which can be seen both in
the ls -l output and the logical read() bytes reported by rfileio.d. There
were 11,582 logical read() calls, which the disk driver satisfied by using
1,700 disk events (aggregation).
The following demonstrates many files being read.
# ./rfileio.d
Read IOPS, top 20 (count)
/usr/bin/amd64/glib-mkenums logical 4
/usr/bin/amd64/glib-genmarshal physical 4
/usr/bin/amd64/gdk-pixbuf-query-loaders logical 4
/usr/bin/amd64/ls logical 5
/usr/bin/amd64/pargs logical 5
/usr/bin/amd64/ps logical 5
/usr/bin/amd64/gconf-merge-tree physical 6
/usr/bin/amd64/cputrack logical 6
/usr/bin/amd64/gconftool-2 physical 6
/usr/bin/amd64/prctl logical 6
/usr/bin/amd64/prstat logical 6
/usr/bin/amd64/glib-genmarshal logical 7
/usr/bin/amd64/truss physical 8
/usr/bin/amd64/sort logical 9
/usr/bin/amd64/prex logical 10
/usr/bin/amd64/gconf-merge-tree logical 13
/usr/bin/amd64/mdb physical 15
/usr/bin/amd64/gconftool-2 logical 15
/usr/bin/amd64/truss logical 26
/usr/bin/amd64/mdb logical 63
Read Bandwidth, top 20 (bytes)
/usr/bin/amd64/prctl logical 36784
/usr/bin/amd64/prctl physical 36864
/usr/bin/amd64/prstat logical 44760
/usr/bin/amd64/prstat physical 45056
/usr/bin/amd64/glib-genmarshal logical 46064
/usr/bin/amd64/glib-genmarshal physical 46080
/usr/bin/amd64/cputrack logical 46912
/usr/bin/amd64/cputrack physical 47104
/usr/bin/amd64/sort logical 65120
/usr/bin/amd64/sort physical 65536
/usr/bin/amd64/prex logical 80968
/usr/bin/amd64/prex physical 81920
/usr/bin/amd64/gconf-merge-tree logical 113592
/usr/bin/amd64/gconf-merge-tree physical 122880
/usr/bin/amd64/gconftool-2 logical 129208
/usr/bin/amd64/gconftool-2 physical 139264
/usr/bin/amd64/truss logical 246360
/usr/bin/amd64/truss physical 262144
/usr/bin/amd64/mdb logical 627456
/usr/bin/amd64/mdb physical 638976
Total File System miss-rate: 81%
^C
The miss-rate was 81%, meaning we are returning around 20% of the data from
the cache. Details for the top 20 files read by-bytes and by-count are listed;
this shows the /usr/bin/amd64/mdb file was read() 63 times, causing 15 disk
reads, and while 627,456 bytes were requested, 638,976 bytes were read from
disk (the extra bytes are due to read-ahead and file system metadata).