1 .TH iopending 1m "$Date:: 2007-08-05 #$" "USER COMMANDS"
3 iopending \- plot number of pending disk events. Uses DTrace.
6 [\-c] [\-d device] [\-f filename] [\-m mount_point] [interval [count]]
8 This samples the number of disk events that are pending and plots a
9 distribution graph. By doing this the
10 "serialness" or "parallelness" of disk behaviour can be distinguished.
11 A high occurance of a pending value of more than 1 is an indication of
14 Since this uses DTrace, only the root user or users with the
15 dtrace_kernel privilege can run this command.
19 stable - needs the io provider.
26 instance name to snoop (eg, dad0)
29 full pathname of file to snoop
32 mountpoint for filesystem to snoop
35 Default output, print I/O summary every 1 second,
40 Print 10 second samples,
46 Print 12 x 5 second samples,
52 Snoop events on the root filesystem only,
60 number of pending events, 0 == idle
63 number of samples @ 1000 Hz
69 total disk read Kb for sample
72 total disk write Kb for sample
78 See the DTraceToolkit for further documentation under the
79 Docs directory. The DTraceToolkit docs may include full worked
80 examples with verbose descriptions explaining the output.
82 iopending will run forever until Ctrl\-C is hit, or the
83 specified count is reached.
88 iosnoop(1M), iotop(1M), dtrace(1M)