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HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | KEYBOARD SHORTCUTS | ENVIRONMENT | SEE ALSO | AUTHOR | COLOPHON |
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IOTOP(8) System Manager's Manual IOTOP(8)
iotop - simple top-like I/O monitor
iotop [OPTIONS]
iotop watches I/O usage information available in the Linux kernel
(requires 2.6.20 or later) and displays a table of current I/O
usage by processes or threads on the system. At least the
CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING,
CONFIG_TASKSTATS and CONFIG_VM_EVENT_COUNTERS options need to be
enabled in your Linux kernel build configuration.
Running iotop as non-root user is possible by adding the NET_ADMIN
capability. This can be done by e.g.:
$ sudo setcap 'cap_net_admin+eip' <path-to>/iotop
Be warned that this will also allow other users to run it and get
access to information that normally should not be available to
them.
iotop displays columns for the I/O bandwidth read and written by
each process/thread during the sampling period. It also displays
the percentage of time the thread/process spent while swapping in
and while waiting on I/O. For each process, its I/O priority
(class/level) is shown.
In addition, the total I/O bandwidth read and written during the
sampling period are displayed at the top of the interface. Total
DISK READ and Total DISK WRITE values represent total read and
write bandwidth between processes and kernel threads on one side
and kernel block device subsystem on the other. While Current DISK
READ and Current DISK WRITE values represent corresponding
bandwidths for current disk I/O between the kernel block device
subsystem and the underlying hardware (HDD, SSD, etc.). Thus Total
and Current values may not be equal at any given moment of time
due to data caching and I/O operations reordering that take place
inside the Linux kernel.
Use the left and right arrows to select the sort column, r or
space to reverse the sorting order, o to toggle the --only option
(this uses the visible values from the GRAPH column or the IO
column in case the GRAPH column is hidden), p to toggle the
--processes option, a to cycle between the --accumulated,
--accum-bw and normal operation, i to change the priority of a
thread or a process's thread, f to change filtering by UID/PID
(--user and --pid options), 1-9 to toggle the visibility of the
respective column, 0 to show all columns, up/down arrows,
page-up/page-down/home/end keys to scroll and q to quit. Any
unrecognized key will be ignored.
All processes or threads that have exited are displayed grayed for
the same time as is visible in the GRAPH column or 3 seconds when
it is hidden. The invalid data points in the GRAPHS column are
displayed inverse or with letter x (see option --dead-x and x
shortcut). When using unicode characters each position contains
two datapoints and only the positions with two invalid data points
are reversed.
It is possible for threads of a process to have different priority
from their main process. This is shown with ! in the PRIO column
of the main process as e.g. !be/4.
Threads activity is always aggregated with and shown inside the
main process.
When showing threads, they always appear below their main process
and are sorted in the same way as the processes.
There are two ways to change the IO priority of a process or
thread - press i and use arrows to select the process or thread
from the visible ones on screen or press i and type its TID (PID
and TID have the same value for the main process). Then use tab
and arrows to change the priority value and confirm with enter.
Shortcuts esc or q will cancel this mode.
To change the UID and PID filters, press f and use tab to select
the UID or PID field, then type the numerical id or n to remove
the filter and confirm with enter. Filtering is always done by TID
because it is unique. Note that for the main process PID is the
same as TID. Shortcuts esc or q will cancel this mode.
Starting with Linux kernel 5.14.x task_delayacct is configurable
at runtime and set to off by default. This setting can be changed
in interactive mode by the Ctrl-T shortcut. In batch mode a
warning is printed when the setting is OFF. From the command line
this can be enabled by:
$ sudo sysctl kernel.task_delayacct=1
and disabled again by:
$ sudo sysctl kernel.task_delayacct=0
It is advisable to keep this option off when not using this or
another monitoring program because when enabled it has some effect
on system performance.
-v, --version
Show the version number and exit
-h, --help
Show usage information and exit
-H, --help-type=TYPE
Set the type of interactive help shown. Accepted values for
TYPE are none, win and inline.
-o, --only
Only show processes or threads actually doing I/O, instead
of showing all processes or threads. This can be
dynamically toggled by pressing o
--no-only
Show all processes or threads
-b, --batch
Turn on non-interactive mode. Useful for logging I/O usage
over time
-n NUM, --iter=NUM
Set the number of iterations before quitting (never quit by
default). This is most useful in non-interactive mode
-d SEC, --delay=SEC
Set the delay between iterations in seconds (1 second by
default). Accepts non-integer values such as 1.1 seconds
-p PID, --pid=PID
A process/thread id to monitor (all by default)
-u USER, --user=USER
A user id to monitor (all by default). The value will
always be resolved first unless it is prefixed by + in
which case it is treated as numeric only. Values that do
not resolve but appear to be numeric are used as numeric
-P, --processes
Only show processes. Normally iotop shows processes and all
threads
--no-processes
Show processes and all threads
-a, --accumulated
Show accumulated I/O instead of bandwidth. In this mode,
iotop shows the amount of I/O processes have done since the
process or iotop started. Note that this option and
--accum-bw are exclusive and they will turn each other off
--no-accumulated
Show bandwidth (useful when changing config file with
--write)
-A, --accum-bw
Show accumulated I/O as bandwidth for the whole sampling
period. In this mode, iotop shows the amount of I/O per
second for the whole period since the process or iotop
started Note that this option and --accumulated are
exclusive and they will turn each other off
--no-accum-bw
Show bandwidth (useful when changing config file with
--write)
-k, --kilobytes
Use kilobytes instead of a human friendly unit. This mode
is useful when scripting the batch mode of iotop. Instead
of choosing the most appropriate unit iotop will display
all sizes in kilobytes
--no-kilobytes
Use human friendly units
-t, --time
Add a timestamp on each line (implies --batch). Each line
will be prefixed by the current time
-c, --fullcmdline
Show processes' full file path and parameters
--no-fullcmdline
Show processes' names only
-1, --hide-pid
Hide PID/TID column
--show-pid
Show PID/TID column
-2, --hide-prio
Hide PRIO column
--show-prio
Show PRIO column
-3, --hide-user
Hide USER column
--show-user
Show USER column
-4, --hide-read
Hide DISK READ column
--show-read
Show DISK READ column
-5, --hide-write
Hide DISK WRITE column
--show-write
Show DISK WRITE column
-6, --hide-swapin
Hide SWAPIN column
--show-swapin
Show SWAPIN column
-7, --hide-io
Hide IO column
--show-io
Show IO column
-8, --hide-graph
Hide GRAPH column
--show-graph
Show GRAPH column
-9, --hide-command
Hide COMMAND column
--show-command
Show COMMAND column
-g TYPE, --grtype=TYPE
Set GRAPH column data source. Accepted values for TYPE are
io, r, w, rw and sw.
-R, --reverse-graph
Reverse GRAPH direction - show most recent values on the
right side
--no-reverse-graph
Do not reverse GRAPH direction - show most recent values on
the left side
-q, --quiet
Suppress headers before each run (implies --batch). This
option can be specified up to three times to suppress the
output of different header lines:
-q column names are only printed on the first
iteration,
-qq column names are never printed,
-qqq the I/O summary is never printed
-x, --dead-x
Show exited processes/threads with letter x instead of
inverse background
--no-dead-x
Show exited processes/threads with inverse background
-e, --hide-exited
Hide exited processes
--show-exited
Show exited processes
-l, --no-color
Do not colorize values
--color
Colorize values. This will override the effect of the
environment variable NO_COLOR when explicitly specified on
the command line.
-T, --hide-time
Do not show time clock in upper right corner
--show-time
Show time clock in upper right corner
--si Use SI units of 1000 when printing values. The default is
non-SI 1024
--no-si
Use non-SI units of 1024 when printing values
--threshold=1..10
Set the threshold to switch to next unit. The default value
is 2
--ascii
Disable using Unicode
--unicode
Use Unicode drawing chars
-N, --inverse
Use inverse interface (black on white)
--filter=REGEX
Filter processes by TID and COMMAND. This will only show
processes where TID or COMMAND are matching the REGEX.
-W, --write
Merge the preceding options to the current config, save the
config and exit. Note that all options after this one will
be ignored.
q, Q Exit
W Save current settings to configuration file in a place
conforming to XDG Base Directory Specification. The
respective path is created in case it does not exist. In
case of error creating or accessing the config file, the
error is silently ignored and the configuration is not
saved.
$XDG_CONFIG_HOME/iotop/iotoprc - if environment variable
XDG_CONFIG_HOME is set.
$HOME/.config/iotop/iotoprc - if environment variable
XDG_CONFIG_HOME is not set but HOME is set.
.config/iotop/iotoprc - if neither XDG_CONFIG_HOME nor HOME
are set.
D Reset all settings to their default values
<space>, r
Toggle sort order
<home> Scroll to the top of the list
<end> Scroll to the bottom of the list
<page-up>
Scroll one screen up
<page-down>
Scroll one screen down
<up> Scroll one line up
<down> Scroll one line down
<right>
Sort by next column
<left> Sort by previous column
<esc> Cancel ionice or filter selection. In case only the help
window is open then close it
o, O Toggle showing only processes with IO activity
p, P Toggle showing processes/threads
a, A Cycle showing accumulated/accum-bw/current values
? Toggle showing inline help
h, H Toggle showing window help
c, C Toggle showing full command line
1, 2, 3, 4, 5, 6, 7, 8, 9
Toggle showing the column (column number corresponds to the
shortcut)
0 Show all columns
g, G Cycle GRAPH source (IO=IO, R=DISK READ , W=DISK WRITE,
R+W=DISK READ+DISK WRITE, SW=SWAPIN). Using g will cycle
forward and G will cycle backward.
R Toggle reverse GRAPH direction
i, I IOnice a process/thread (depends on process/thread display
mode)
f, F Change UID and PID filters
u, U Toggle using Unicode/ASCII characters for pseudo graph
l, L Toggle colorizing values
n, N Toggle inverse interface (black on white)
x, X Toggle the display mode of exited processes/threads between
letter x and inverse background
e, E Toggle the display of exited processes
T Toggle the display of time clock in upper right corner
s, S Toggle freeze of data collection
Ctrl-B, b
Toggle SI units
Ctrl-R, t
Cycle unit threshold
Ctrl-T Toggle task_delayacct kernel sysctl
Ctrl-L Redraw screen
/ Change search regular expression. While the search regular
expression is being edited, there is an indicator next to
it that shows if the expression is valid. The search is
confirmed by <enter> or cancelled by <esc>.
List of shortcuts in the editor:
<esc> Cancel editing and remove the regular expression
filter
<enter>
Confirm the current regular expression and exit edit
mode. In case the regular expression is empty or
invalid it will match everything.
Alt/Meta-<backspace>, Ctrl-W
Delete one word from cursor to the left
Alt/Meta-D
Delete one word from cursor to the right
Alt/Meta-B, Ctrl-<left>
Move the cursor to the beginning of the word on the
left
Alt/Meta-F, Ctrl-<right>
Move the cursor after the end of the word on the
right
Ctrl-A, <home>
Move the cursor to the leftmost position
Ctrl-E, <end>
Move the cursor after the last character
Ctrl-B, <left>
Move the cursor to the left
Ctrl-F, <right>
Move the cursor to the right
Ctrl-H, <backspace>
Delete the character left of cursor
Ctrl-D, <del>
Delete the character under the cursor
Ctrl-K Delete from the character under the cursor to the
end of the line
Ctrl-U Delete everything
[anything-else]
Non-printable characters are ignored. Normal
characters are inserted before the character under
the cursor. UTF-8 sequences are parsed and treated
as a single character. Unicode combining characters
will be appended to the character under the cursor.
NO_COLOR
As per the recommendation of https://www.no-color.org/
iotop honors the contents of the environment variable
NO_COLOR and when it is set to a non empty string, all
color output is suppressed.
HOME, XDG_CONFIG_HOME
Used to determine the config file path. See the W shortcut
for details.
IOTOP_NO_RENICE
Disable the i shortcut. The user will not be able to change
processes' nice values.
ionice(1), top(1), vmstat(1), atop(1), htop(1)
The original Python iotop implementation was written by Guillaume
Chazarain. This rewrite in C was started in 2014 by Vyacheslav
Trushkin and reworked to include all missing features from the
original Python code and several new ones from 2020 to 2025 by
Boian Bonev.
This manual page was started by Paul Wise for the Debian project
and is placed in the public domain.
This page is part of the iotop (a simple top-like I/O monitor)
project. Information about the project can be found at
⟨https://github.com/Tomas-M/iotop⟩. If you have a bug report for
this manual page, see ⟨https://github.com/Tomas-M/iotop/issues⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/Tomas-M/iotop⟩ on 2026-01-16. (At that time,
the date of the most recent commit that was found in the
repository was 2025-11-24.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
January 13, 2025 IOTOP(8)
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HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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