\input texinfo @setfilename niceload.info @documentencoding utf-8 @settitle niceload - slow down a program when the load average is above a certain limit @node Top @top niceload @chapter NAME @anchor{NAME} niceload - slow down a program when the load average is above a certain limit @chapter SYNOPSIS @anchor{SYNOPSIS} @strong{niceload} [-v] [-h] [-n nice] [-I io] [-L load] [-M mem] [-N] [-t time] [-s time|-f factor] ( command | -p PID ) @chapter DESCRIPTION @anchor{DESCRIPTION} GNU @strong{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 @strong{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, ... @chapter OPTIONS @anchor{OPTIONS} @table @asis @item @strong{-f} @emph{FACTOR} @anchor{@strong{-f} @emph{FACTOR}} @item @strong{--factor} @emph{FACTOR} @anchor{@strong{--factor} @emph{FACTOR}} Suspend time factor. Dynamically set @strong{-s} as amount over limit * factor. Default is 1. @item @strong{-H} @anchor{@strong{-H}} @item @strong{--hard} @anchor{@strong{--hard}} Hard limit. @strong{--hard} will suspend the process until the system is under the limits. The default is @strong{--soft}. @item @strong{--io} @emph{iolimit} @anchor{@strong{--io} @emph{iolimit}} @item @strong{-I} @emph{iolimit} @anchor{@strong{-I} @emph{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. @strong{--io} will set both @strong{--start-io} and @strong{run-io}. @item @strong{--load} @emph{loadlimit} @anchor{@strong{--load} @emph{loadlimit}} @item @strong{-L} @emph{loadlimit} @anchor{@strong{-L} @emph{loadlimit}} Limit for load average. @strong{--load} will set both @strong{--start-load} and @strong{run-load}. @item @strong{--mem} @emph{memlimit} @anchor{@strong{--mem} @emph{memlimit}} @item @strong{-M} @emph{memlimit} @anchor{@strong{-M} @emph{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 @emph{memlimit} can be postfixed with K, M, G, T, or P which would multiply the size with 1024, 1048576, 1073741824, or 1099511627776 respectively. @strong{--mem} will set both @strong{--start-mem} and @strong{run-mem}. @item @strong{--noswap} @anchor{@strong{--noswap}} @item @strong{-N} @anchor{@strong{-N}} No swapping. If the system is swapping both in and out it is a good indication that the system is memory stressed. @strong{--noswap} is over limit if the system is swapping both in and out. @strong{--noswap} will set both @strong{--start-noswap} and @strong{run-noswap}. @item @strong{-n} @emph{niceness} @anchor{@strong{-n} @emph{niceness}} @item @strong{--nice} @emph{niceness} @anchor{@strong{--nice} @emph{niceness}} Sets niceness. See @strong{nice}(1). @item @strong{-p} @emph{PID} @anchor{@strong{-p} @emph{PID}} @item @strong{--pid} @emph{PID} @anchor{@strong{--pid} @emph{PID}} Process ID of process to suspend. @item @strong{--quote} @anchor{@strong{--quote}} @item @strong{-q} @anchor{@strong{-q}} Quote the command line. Useful if the command contains chars like *, $, >, and " that should not be interpreted by the shell. @item @strong{--run-io} @emph{iolimit} @anchor{@strong{--run-io} @emph{iolimit}} @item @strong{--ri} @emph{iolimit} @anchor{@strong{--ri} @emph{iolimit}} @item @strong{--run-load} @emph{loadlimit} @anchor{@strong{--run-load} @emph{loadlimit}} @item @strong{--rl} @emph{loadlimit} @anchor{@strong{--rl} @emph{loadlimit}} @item @strong{--run-mem} @emph{memlimit} @anchor{@strong{--run-mem} @emph{memlimit}} @item @strong{--rm} @emph{memlimit} @anchor{@strong{--rm} @emph{memlimit}} Run limit. The running program will be slowed down if the system is above the limit. See: @strong{--io}, @strong{--load}, @strong{--mem}, @strong{--noswap}. @item @strong{--start-io} @emph{iolimit} @anchor{@strong{--start-io} @emph{iolimit}} @item @strong{--si} @emph{iolimit} @anchor{@strong{--si} @emph{iolimit}} @item @strong{--start-load} @emph{loadlimit} @anchor{@strong{--start-load} @emph{loadlimit}} @item @strong{--sl} @emph{loadlimit} @anchor{@strong{--sl} @emph{loadlimit}} @item @strong{--start-mem} @emph{memlimit} @anchor{@strong{--start-mem} @emph{memlimit}} @item @strong{--sm} @emph{memlimit} @anchor{@strong{--sm} @emph{memlimit}} Start limit. The program will not start until the system is below the limit. See: @strong{--io}, @strong{--load}, @strong{--mem}, @strong{--noswap}. @item @strong{--soft} @anchor{@strong{--soft}} @item @strong{-S} @anchor{@strong{-S}} Soft limit. @strong{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. @item @strong{--suspend} @emph{SEC} @anchor{@strong{--suspend} @emph{SEC}} @item @strong{-s} @emph{SEC} @anchor{@strong{-s} @emph{SEC}} Suspend time. Suspend the command this many seconds when the max load average is reached. @item @strong{--recheck} @emph{SEC} @anchor{@strong{--recheck} @emph{SEC}} @item @strong{-t} @emph{SEC} @anchor{@strong{-t} @emph{SEC}} Recheck load time. Sleep SEC seconds before checking load again. Default is 1 second. @item @strong{--verbose} @anchor{@strong{--verbose}} @item @strong{-v} @anchor{@strong{-v}} Verbose. Print some extra output on what is happening. Use @strong{-v} until you know what your are doing. @end table @chapter EXAMPLE: See niceload in action @anchor{EXAMPLE: See niceload in action} In terminal 1 run: top In terminal 2 run: @strong{niceload perl -e '$|=1;do@{$l==$r or print "."; $l=$r@}until(($r=time-$^T)}>@strong{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. @chapter EXAMPLE: Run updatedb @anchor{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: @strong{niceload -L 2 updatedb} @chapter EXAMPLE: Run rsync @anchor{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: @strong{niceload -L 3.4 -f 12 rsync -Ha /home/ /backup/home/} @chapter EXAMPLE: Ensure enough disk cache @anchor{EXAMPLE: Ensure enough disk cache} Assume the program @strong{foo} uses 2 GB files intensively. @strong{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: @strong{niceload --hard --run-mem 2g foo} This will not guarantee that the 2 GB memory will be used for the files for @strong{foo}, but it will stop @strong{foo} if the memory for disk cache is too low. @chapter ENVIRONMENT VARIABLES @anchor{ENVIRONMENT VARIABLES} None. In future versions $NICELOAD will be able to contain default settings. @chapter EXIT STATUS @anchor{EXIT STATUS} Exit status should be the same as the command being run (untested). @chapter REPORTING BUGS @anchor{REPORTING BUGS} Report bugs to <bug-parallel@@gnu.org>. @chapter AUTHOR @anchor{AUTHOR} Copyright (C) 2004-11-19 Ole Tange, http://ole.tange.dk Copyright (C) 2005,2006,2006,2008,2009,2010 Ole Tange, http://ole.tange.dk Copyright (C) 2010,2011 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc. @chapter LICENSE @anchor{LICENSE} Copyright (C) 2010 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 <http://www.gnu.org/licenses/>. @section Documentation license I @anchor{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. @section Documentation license II @anchor{Documentation license II} You are free: @table @asis @item @strong{to Share} @anchor{@strong{to Share}} to copy, distribute and transmit the work @item @strong{to Remix} @anchor{@strong{to Remix}} to adapt the work @end table Under the following conditions: @table @asis @item @strong{Attribution} @anchor{@strong{Attribution}} 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). @item @strong{Share Alike} @anchor{@strong{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. @end table With the understanding that: @table @asis @item @strong{Waiver} @anchor{@strong{Waiver}} Any of the above conditions can be waived if you get permission from the copyright holder. @item @strong{Public Domain} @anchor{@strong{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. @item @strong{Other Rights} @anchor{@strong{Other Rights}} In no way are any of the following rights affected by the license: @itemize @item Your fair dealing or fair use rights, or other applicable copyright exceptions and limitations; @item The author's moral rights; @item Rights other persons may have either in the work itself or in how the work is used, such as publicity or privacy rights. @end itemize @end table @table @asis @item @strong{Notice} @anchor{@strong{Notice}} For any reuse or distribution, you must make clear to others the license terms of this work. @end table A copy of the full license is included in the file as cc-by-sa.txt. @chapter DEPENDENCIES @anchor{DEPENDENCIES} GNU @strong{niceload} uses Perl, and the Perl modules POSIX, and Getopt::Long. @chapter SEE ALSO @anchor{SEE ALSO} @strong{parallel}(1), @strong{nice}(1), @strong{uptime}(1) @bye