1IOTOP(8) System Manager's Manual IOTOP(8)
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6 iotop - simple top-like I/O monitor
7
9 iotop [OPTIONS]
10
12 iotop watches I/O usage information available in the Linux kernel (re‐
13 quires 2.6.20 or later) and displays a table of current I/O usage by
14 processes or threads on the system. At least the CONFIG_TASK_DE‐
15 LAY_ACCT, CONFIG_TASK_IO_ACCOUNTING, CONFIG_TASKSTATS and CON‐
16 FIG_VM_EVENT_COUNTERS options need to be enabled in your Linux kernel
17 build configuration.
18 Running iotop as non-root user is possible by adding the NET_ADMIN ca‐
20 pability. This can be done by e.g.:
21 $ sudo setcap 'cap_net_admin+eip' <path-to>/iotop
23 Be warned that this will also allow other users to run it and get ac‐
25 cess to information that normally should not be available to them.
26 iotop displays columns for the I/O bandwidth read and written by each
28 process/thread during the sampling period. It also displays the per‐
29 centage of time the thread/process spent while swapping in and while
30 waiting on I/O. For each process, its I/O priority (class/level) is
31 shown.
32 In addition, the total I/O bandwidth read and written during the sam‐
34 pling period are displayed at the top of the interface. Total DISK
35 READ and Total DISK WRITE values represent total read and write band‐
36 width between processes and kernel threads on one side and kernel block
37 device subsystem on the other. While Current DISK READ and Current DISK
38 WRITE values represent corresponding bandwidths for current disk I/O
39 between the kernel block device subsystem and the underlying hardware
40 (HDD, SSD, etc.). Thus Total and Current values may not be equal at any
41 given moment of time due to data caching and I/O operations reordering
42 that take place inside the Linux kernel.
43 Use the left and right arrows to select the sort column, r or space to
45 reverse the sorting order, o to toggle the --only option (this uses the
46 visible values from the GRAPH column or the IO column in case the GRAPH
47 column is hidden), p to toggle the --processes option, a to toggle the
48 --accumulated option, i to change the priority of a thread or a
49 process's thread, f to change filtering by UID/PID (--user and --pid
50 options), 1-9 to toggle the visibility of the respective column, 0 to
51 show all columns, up/down arrows, page-up/page-down/home/end keys to
52 scroll and q to quit. Any unrecognized key will be ignored.
53 All processes or threads that have exited are displayed grayed for the
55 same time as is visible in the GRAPH column or 3 seconds when it is
56 hidden. The invalid data points in the GRAPHS column are displayed in‐
57 verse or with letter x (see option --dead-x and x shortcut). When using
58 unicode characters each position contains two datapoints and only the
59 positions with two invalid data points are reversed.
60 It is possible for threads of a process to have different priority from
62 their main process. This is shown with ! in the PRIO column of the main
63 process as e.g. !be/4.
64 Threads activity is always aggregated with and shown inside the main
66 process.
67 When showing threads, they always appear below their main process and
69 are sorted in the same way as the processes.
70 There are two ways to change the IO priority of a process or thread -
72 press i and use arrows to select the process or thread from the visible
73 ones on screen or press i and type its TID (PID and TID have the same
74 value for the main process). Then use tab and arrows to change the pri‐
75 ority value and confirm with enter. Shortcuts esc or q will cancel this
76 mode.
77 To change the UID and PID filters, press f and use tab to select the
79 UID or PID field, then type the numerical id or n to remove the filter
80 and confirm with enter. Filtering is always done by TID because it is
81 unique. Note that for the main process PID is the same as TID. Short‐
82 cuts esc or q will cancel this mode.
83 Starting with Linux kernel 5.14.x task_delayacct is configurable at
85 runtime and set to off by default. This setting can be changed in in‐
86 teractive mode by the Ctrl-T shortcut. In batch mode a warning is
87 printed when the setting is OFF. From the command line this can be en‐
88 abled by:
89 $ sudo sysctl kernel.task_delayacct=1
91 and disabled again by:
93 $ sudo sysctl kernel.task_delayacct=0
95 It is advisable to keep this option off when not using this or another
97 monitoring program because when enabled it has some effect on system
98 performance.
99
101 -v, --version
102 Show the version number and exit
103 -h, --help
105 Show usage information and exit
106 -o, --only
108 Only show processes or threads actually doing I/O, instead of
109 showing all processes or threads. This can be dynamically tog‐
110 gled by pressing o
111 -b, --batch
113 Turn on non-interactive mode. Useful for logging I/O usage over
114 time
115 -n NUM, --iter=NUM
117 Set the number of iterations before quitting (never quit by de‐
118 fault). This is most useful in non-interactive mode
119 -d SEC, --delay=SEC
121 Set the delay between iterations in seconds (1 second by de‐
122 fault). Accepts non-integer values such as 1.1 seconds
123 -p PID, --pid=PID
125 A process/thread id to monitor (all by default)
126 -u USER, --user=USER
128 A user id to monitor (all by default). The value will always be
129 resolved first unless it is prefixed by + in which case it is
130 threated as numeric only. Values that do not resolve but appear
131 to be numeric are used as numeric
132 -P, --processes
134 Only show processes. Normally iotop shows processes and all
135 threads
136 -a, --accumulated
138 Show accumulated I/O instead of bandwidth. In this mode, iotop
139 shows the amount of I/O processes have done since iotop started
140 -k, --kilobytes
142 Use kilobytes instead of a human friendly unit. This mode is
143 useful when scripting the batch mode of iotop. Instead of choos‐
144 ing the most appropriate unit iotop will display all sizes in
145 kilobytes
146 -t, --time
148 Add a timestamp on each line (implies --batch). Each line will
149 be prefixed by the current time
150 -c, --fullcmdline
152 Show processes' full file path and parameters
153 -1, --hide-pid
155 Hide PID/TID column
156 -2, --hide-prio
158 Hide PRIO column
159 -3, --hide-user
161 Hide USER column
162 -4, --hide-read
164 Hide DISK READ column
165 -5, --hide-write
167 Hide DISK WRITE column
168 -6, --hide-swapin
170 Hide SWAPIN column
171 -7, --hide-io
173 Hide IO column
174 -8, --hide-graph
176 Hide GRAPH column
177 -9, --hide-command
179 Hide COMMAND column
180 -q, --quiet
182 Suppress some lines of header (implies --batch). This option can
183 be specified up to three times to remove header lines
184 -q column names are only printed on the first iteration,
185 -qq column names are never printed,
186 -qqq the I/O summary is never printed
187 -x, --dead-x
189 Show dead processes/threads with letter x instead of inverse
190 background
191
193 q, Q Exit
194 <space>, r, R
196 Toggle sort order
197 <home> Scroll to the top of the list
199 <end> Scroll to the bottom of the list
201 <page-up>
203 Scroll one screen up
204 <page-down>
206 Scroll one screen down
207 <up> Scroll one line up
209 <down> Scroll one line down
211 <right>
213 Sort by next column
214 <left> Sort by previous column
216 <esc> Cancel ionice or filter selection. In case only the help window
218 is open then close it
219 o, O Toggle showing only processes with IO activity
221 p, P Toggle showing processes/threads
223 a, A Toggle showing accumulated/current values
225 ?, h, H
227 Toggle showing shortcut help
228 c, C Toggle showing full command line
230 1, 2, 3, 4, 5, 6, 7, 8, 9
232 Toggle showing the column (column number corresponds to the
233 shortcut)
234 0 Show all columns
236 i, I IOnice a process/thread (depends on process/thread display mode)
238 f, F Change UID and PID filters
240 u, U Toggle using Unicode/ASCII characters for pseudo graph
242 x, X Toggle the display mode of exited processes/threads between let‐
244 ter x and inverse background
245 s, S Toggle freeze of data collection
247 Ctrl-T Toggle task_delayacct kernel sysctl
249
251 ionice(1), top(1), vmstat(1), atop(1), htop(1)
252
254 The original Python iotop implementation was written by Guillaume Chaz‐
255 arain. This rewrite in C was started in 2014 by Vyacheslav Trushkin
256 and reworked to include all missing features from the original Python
257 code and several new ones in 2020 and 2021 by Boian Bonev.
258 This manual page was started by Paul Wise for the Debian project and is
260 placed in the public domain.
261 January 28, 2021 IOTOP(8)