man pages section 1: User Commands

Exit Print View

Updated: July 2014

niceload (1)


niceload - slow down a program when the load average is above a certain limit


niceload [-v] [-h] [-n nice] [-I io] [-L load] [-M mem] [-N]
[--sensor program] [-t time] [-s time|-f factor] ( command |
-p PID )


parallel                                              NICELOAD(1)

     niceload - slow down a program when the load average is
     above a certain limit

     niceload [-v] [-h] [-n nice] [-I io] [-L load] [-M mem] [-N]
     [--sensor program] [-t time] [-s time|-f factor] ( command |
     -p PID )

     GNU niceload will slow down a program when the load average
     (or other system activity) is above a certain limit. When
     the limit is reached the program will be suspended for some
     time. Then resumed again for some time.  Then the load
     average is checked again and we start over.

     Instead of load average niceload can also look at disk I/O,
     amount of free memory, or swapping activity.

     If the load is 3.00 then the default settings will run a
     program like this:

     run 1 second, suspend (3.00-1.00) seconds, run 1 second,
     suspend (3.00-1.00) seconds, run 1 second, ...

     -f FACTOR
     --factor FACTOR
              Suspend time factor. Dynamically set -s as amount
              over limit * factor. Default is 1.

     --hard   Hard limit. --hard will suspend the process until
              the system is under the limits. The default is

     --io iolimit
     -I iolimit
              Limit for I/O. The amount of disk I/O will be
              computed as a value 0 - 10, where 0 is no I/O and
              10 is at least one disk is 100% satuated.

              --io will set both --start-io and run-io.

     --load loadlimit
     -L loadlimit
              Limit for load average.

              --load will set both --start-load and run-load.

     --mem memlimit
     -M memlimit

20121122             Last change: 2012-11-21                    1

parallel                                              NICELOAD(1)

              Limit for free memory. This is the amount of bytes
              available as free + cache. This limit is treated
              opposite other limits: If the system is above the
              limit the program will run, if it is below the
              limit the program will stop

              memlimit can be postfixed with K, M, G, T, or P
              which would multiply the size with 1024, 1048576,
              1073741824, or 1099511627776 respectively.

              --mem will set both --start-mem and run-mem.

     -N       No swapping. If the system is swapping both in and
              out it is a good indication that the system is
              memory stressed.

              --noswap is over limit if the system is swapping
              both in and out.

              --noswap will set both --start-noswap and run-

     -n niceness
     --nice niceness
              Sets niceness. See nice(1).

     -p PID
     --pid PID
              Process ID of process to suspend.

     -q       Quote the command line. Useful if the command
              contains chars like *, $, >, and " that should not
              be interpreted by the shell.

     --run-io iolimit
     --ri iolimit
     --run-load loadlimit
     --rl loadlimit
     --run-mem memlimit
     --rm memlimit
              Run limit. The running program will be slowed down
              if the system is above the limit. See: --io,
              --load, --mem, --noswap.

     --sensor sensor program (alpha testing)
              Read sensor. Use sensor program to read a sensor.

              This will keep the CPU temperature below 80 deg C
              on GNU/Linux:

20121122             Last change: 2012-11-21                    2

parallel                                              NICELOAD(1)

                niceload -l 80000 -f 0.001 --sensor 'sort -n /sys/devices/platform/coretemp*/temp*_input' gzip *

              This will stop if the disk space < 100000.

                niceload -H -l -100000 --sensor "df . | awk '{ print \$4 }'" echo

     --start-io iolimit
     --si iolimit
     --start-load loadlimit
     --sl loadlimit
     --start-mem memlimit
     --sm memlimit
              Start limit. The program will not start until the
              system is below the limit. See: --io, --load,
              --mem, --noswap.

     -S       Soft limit. niceload will suspend a process for a
              while and then let it run for a second thus only
              slowing down a process while the system is over one
              of the given limits. This is the default.

     --suspend SEC
     -s SEC   Suspend time. Suspend the command this many seconds
              when the max load average is reached.

     --recheck SEC
     -t SEC   Recheck load time. Sleep SEC seconds before
              checking load again. Default is 1 second.

     -v       Verbose. Print some extra output on what is
              happening. Use -v until you know what your are

EXAMPLE: See niceload in action
     In terminal 1 run: top

     In terminal 2 run:

     niceload -q perl -e '$|=1;do{$l==$r or print ".";

     This will print a '.' every second for 50 seconds and eat a
     lot of CPU. When the load rises to 1.0 the process is

EXAMPLE: Run updatedb
     Running updatedb can often starve the system for disk I/O
     and thus result in a high load.

20121122             Last change: 2012-11-21                    3

parallel                                              NICELOAD(1)

     Run updatedb but suspend updatedb if the load is above 2.00:

     niceload -L 2 updatedb

EXAMPLE: Run rsync
     rsync can just like updatedb starve the system for disk I/O
     and thus result in a high load.

     Run rsync but keep load below 3.4. If load reaches 7 sleep
     for (7-3.4)*12 seconds:

     niceload -L 3.4 -f 12 rsync -Ha /home/ /backup/home/

EXAMPLE: Ensure enough disk cache
     Assume the program foo uses 2 GB files intensively. foo will
     run fast if the files are in disk cache and be slow as a
     crawl if they are not in the cache.

     To ensure 2 GB are reserved for disk cache run:

     niceload --hard --run-mem 2g foo

     This will not guarantee that the 2 GB memory will be used
     for the files for foo, but it will stop foo if the memory
     for disk cache is too low.

     None. In future versions $NICELOAD will be able to contain
     default settings.

     Exit status should be the same as the command being run

     Report bugs to <>.

     Copyright (C) 2004-11-19 Ole Tange,

     Copyright (C) 2005,2006,2006,2008,2009,2010 Ole Tange,

     Copyright (C) 2010,2011,2012 Ole Tange,
     and Free Software Foundation, Inc.

     Copyright (C) 2010,2011,2012 Free Software Foundation, Inc.

     This program is free software; you can redistribute it
     and/or modify it under the terms of the GNU General Public
     License as published by the Free Software Foundation; either

20121122             Last change: 2012-11-21                    4

parallel                                              NICELOAD(1)

     version 3 of the License, or at your option any later

     This program is distributed in the hope that it will be
     useful, but WITHOUT ANY WARRANTY; without even the implied
     PURPOSE.  See the GNU General Public License for more

     You should have received a copy of the GNU General Public
     License along with this program.  If not, see

  Documentation license I
     Permission is granted to copy, distribute and/or modify this
     documentation under the terms of the GNU Free Documentation
     License, Version 1.3 or any later version published by the
     Free Software Foundation; with no Invariant Sections, with
     no Front-Cover Texts, and with no Back-Cover Texts.  A copy
     of the license is included in the file fdl.txt.

  Documentation license II
     You are free:

     to Share to copy, distribute and transmit the work

     to Remix to adapt the work

     Under the following conditions:

              You must attribute the work in the manner specified
              by the author or licensor (but not in any way that
              suggests that they endorse you or your use of the

     Share Alike
              If you alter, transform, or build upon this work,
              you may distribute the resulting work only under
              the same, similar or a compatible license.

     With the understanding that:

     Waiver   Any of the above conditions can be waived if you
              get permission from the copyright holder.

     Public Domain
              Where the work or any of its elements is in the
              public domain under applicable law, that status is
              in no way affected by the license.

     Other Rights

20121122             Last change: 2012-11-21                    5

parallel                                              NICELOAD(1)

              In no way are any of the following rights affected
              by the license:

              o Your fair dealing or fair use rights, or other
                applicable copyright exceptions and limitations;

              o The author's moral rights;

              o Rights other persons may have either in the work
                itself or in how the work is used, such as
                publicity or privacy rights.

     Notice   For any reuse or distribution, you must make clear
              to others the license terms of this work.

     A copy of the full license is included in the file as

     GNU niceload uses Perl, and the Perl modules POSIX, and

     See attributes(5) for descriptions of the following

     |Availability   | shell/parallel   |
     |Stability      | Uncommitted      |
     parallel(1), nice(1), uptime(1)

     This software was built from source available at  The original
     community source was downloaded from

     Further information about this software can be found on the
     open source community website at

20121122             Last change: 2012-11-21                    6