NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | AUTHOR | COLOPHON

IOTOP(8)                   System Manager's Manual                  IOTOP(8)

NAME         top

       iotop - simple top-like I/O monitor

SYNOPSIS         top

       iotop [OPTIONS]

DESCRIPTION         top

       iotop watches I/O usage information output by 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.

       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 is 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 the 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 kernel block device subsystem and 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 Linux kernel.

       Use the left and right arrows to change the sorting, r to reverse the
       sorting order, o to toggle the --only option, p to toggle the
       --processes option, a to toggle the --accumulated option, q to quit
       or i to change the priority of a thread or a process' thread(s). Any
       other key will force a refresh.

OPTIONS         top

       --version
              Show the version number and exit

       -h, --help
              Show usage information and exit

       -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.

       -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 list of processes/threads to monitor (all by default).

       -u USER, --user=USER
              A list of users to monitor (all by default)

       -P, --processes
              Only show processes. Normally iotop shows 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 iotop
              started.

       -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.

       -t, --time
              Add a timestamp on each line (implies --batch). Each line will
              be prefixed by the current time.

       -q, --quiet
              suppress some lines of header (implies --batch). This option
              can be specified up to three times to remove header lines.

       --no-help
              Suppress the keyboard shortcuts help display.
              -q     column names are only printed on the first iteration,
              -qq    column names are never printed,
              -qqq   the I/O summary is never printed.

SEE ALSO         top

       ionice(1), top(1), vmstat(1), atop(1), htop(1)

AUTHOR         top

       iotop was written by Guillaume Chazarain.

       This manual page was started by Paul Wise for the Debian project and
       is placed in the public domain.

COLOPHON         top

       This page is part of the iotop (a simple top-like I/O monitor)
       project.  Information about the project can be found at 
       ⟨http://guichaz.free.fr/iotop/⟩.  If you have a bug report for this
       manual page, send it to guichaz@gmail.com.  This page was obtained
       from the project's upstream Git repository
       ⟨git://repo.or.cz/iotop.git⟩ on 2017-11-25.  (At that time, the date
       of the most recent commit that was found in the repository was
       2017-06-17.)  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

                                 April 2009                         IOTOP(8)