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       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 )


       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, ...


                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

       --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 out.

                --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 limit.

                --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
                Process ID of process to suspend. You can specify multiple process IDs with
                multiple -p PID.

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

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

                  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

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

       -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 "."; $l=$r}until(($r=time-$^T)>50)'

       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

       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 (untested).


       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,


       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
       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 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
       See the GNU 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 <>.

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


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