Go to main content

man pages section 1: User Commands

Exit Print View

Updated: Wednesday, February 9, 2022

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 [-p PID ...]
| --prg program )


NICELOAD(1)                        parallel                        NICELOAD(1)

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

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

       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

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

                Suspend if the system is running on battery. Shorthand for: -l
                -1 --sensor 'cat /sys/class/power_supply/BAT0/status
                /proc/acpi/battery/BAT0/state 2>/dev/null | grep -i -q
                discharging; echo $?'

       -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 --soft.

       --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% saturated.

                --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
                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

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

       --net    Shorthand for --nethops 3.

       --nethops h
                Network nice. Pause if the internet connection is overloaded.

                niceload finds a router h hops closer to the internet. It
                pings this every second. If the latency is more than 50%
                bigger than the median, it is regarded as being over the

                --nethops can be combined with --hard. Without --hard the
                program may be able to queue up so much traffic that it will
                take longer than the --suspend time to clear it. --hard is
                useful for traffic that does not break by being suspended for
                a longer time.

                --nethops can be combined with a high --suspend. This way a
                program can be allowed to do a bit of traffic now and then.
                This is useful to keep the connection alive.

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

       -p PID[,PID]
       --pid PID[,PID]
                Process IDs of processes to suspend. You can specify multiple
                process IDs with multiple -p PID or by separating the PIDs
                with comma.

       --prg program
       --program program
                Name of running program to suspend. You can specify multiple
                programs with multiple --prg program. If no processes with the
                name program is found, niceload with search for substrings
                containing program.

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

       --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
                Read sensor. Use sensor program to read a sensor.

                This will keep the CPU temperature below 80 deg C on

                  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

       --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 doing.

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 suspended.

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

       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

       Exit status should be the same as the command being run (untested).

       Report bugs to <bug-parallel@gnu.org>.

       Copyright (C) 2004-11-19 Ole Tange, http://ole.tange.dk

       Copyright (C) 2005-2010 Ole Tange, http://ole.tange.dk

       Copyright (C) 2010-2020 Ole Tange, http://ole.tange.dk and 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 version 3 of the License, or at your
       option any later version.

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

       You should have received a copy of the GNU General Public License along
       with this program.  If not, see <http://www.gnu.org/licenses/>.

   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 work).

       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

       Other Rights
                In no way are any of the following rights affected by the

                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

       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 cc-by-sa.txt.

       GNU niceload uses Perl, and the Perl modules POSIX, and Getopt::Long.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | shell/parallel   |
       |Stability      | Uncommitted      |

       parallel(1), nice(1), uptime(1)

       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at https://www.gnu.org/software/parallel.

20200122                          2020-01-27                       NICELOAD(1)