1IOTOP(8) System Manager's Manual IOTOP(8)
2
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
41 any given moment of time due to data caching and I/O operations re‐
42 ordering 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
75 priority value and confirm with enter. Shortcuts esc or q will cancel
76 this 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
85 -v, --version
86 Show the version number and exit
87 -h, --help
89 Show usage information and exit
90 -o, --only
92 Only show processes or threads actually doing I/O, instead of
93 showing all processes or threads. This can be dynamically tog‐
94 gled by pressing o
95 -b, --batch
97 Turn on non-interactive mode. Useful for logging I/O usage over
98 time
99 -n NUM, --iter=NUM
101 Set the number of iterations before quitting (never quit by de‐
102 fault). This is most useful in non-interactive mode
103 -d SEC, --delay=SEC
105 Set the delay between iterations in seconds (1 second by de‐
106 fault). Accepts non-integer values such as 1.1 seconds
107 -p PID, --pid=PID
109 A process/thread id to monitor (all by default)
110 -u USER, --user=USER
112 A user id to monitor (all by default). The value will always be
113 resolved first unless it is prefixed by + in which case it is
114 threated as numeric only. Values that do not resolve but appear
115 to be numeric are used as numeric
116 -P, --processes
118 Only show processes. Normally iotop shows processes and all
119 threads
120 -a, --accumulated
122 Show accumulated I/O instead of bandwidth. In this mode, iotop
123 shows the amount of I/O processes have done since iotop started
124 -k, --kilobytes
126 Use kilobytes instead of a human friendly unit. This mode is
127 useful when scripting the batch mode of iotop. Instead of
128 choosing the most appropriate unit iotop will display all sizes
129 in kilobytes
130 -t, --time
132 Add a timestamp on each line (implies --batch). Each line will
133 be prefixed by the current time
134 -c, --fullcmdline
136 Show processes' full file path and parameters
137 -1, --hide-pid
139 Hide PID/TID column
140 -2, --hide-prio
142 Hide PRIO column
143 -3, --hide-user
145 Hide USER column
146 -4, --hide-read
148 Hide DISK READ column
149 -5, --hide-write
151 Hide DISK WRITE column
152 -6, --hide-swapin
154 Hide SWAPIN column
155 -7, --hide-io
157 Hide IO column
158 -8, --hide-graph
160 Hide GRAPH column
161 -9, --hide-command
163 Hide COMMAND column
164 -q, --quiet
166 Suppress some lines of header (implies --batch). This option can
167 be specified up to three times to remove header lines
168 -q column names are only printed on the first iteration,
169 -qq column names are never printed,
170 -qqq the I/O summary is never printed
171 -x, --dead-x
173 Show dead processes/threads with letter x instead of inverse
174 background
175
177 q, Q Exit
178 <space>, r, R
180 Toggle sort order
181 <home> Scroll to the top of the list
183 <end> Scroll to the bottom of the list
185 <page-up>
187 Scroll one screen up
188 <page-down>
190 Scroll one screen down
191 <up> Scroll one line up
193 <down> Scroll one line down
195 <right>
197 Sort by next column
198 <left> Sort by previous column
200 o, O Toggle showing only processes with IO activity
202 p, P Toggle showing processes/threads
204 a, A Toggle showing accumulated/current values
206 ?, h, H
208 Toggle showing shortcut help
209 c, C Toggle showing full command line
211 1, 2, 3, 4, 5, 6, 7, 8, 9
213 Toggle showing the column (column number corresponds to the
214 shortcut)
215 0 Show all columns
217 i, I IOnice a process/thread (depends on process/thread display mode)
219 f, F Change UID and PID filters
221 u, U Toggle using Unicode/ASCII characters for pseudo graph
223 x, X Toggle the display mode of exited processes/threads between let‐
225 ter x and inverse background
226 s, S Toggle freeze of data collection
228
230 ionice(1), top(1), vmstat(1), atop(1), htop(1)
231
233 The original Python iotop implementation was written by Guillaume Chaz‐
234 arain. This rewrite in C was started in 2014 by Vyacheslav Trushkin
235 and reworked to include all missing features from the original Python
236 code and several new ones in 2020 and 2021 by Boian Bonev.
237 This manual page was started by Paul Wise for the Debian project and is
239 placed in the public domain.
240 January 28, 2021 IOTOP(8)