NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLE: See niceload in action
EXAMPLE: Run updatedb
EXAMPLE: Run rsync
ENVIRONMENT VARIABLES
EXIT STATUS
REPORTING BUGS
AUTHOR
LICENSE

NAME

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

SYNOPSIS

niceload [-v] [-n nice] [-l load] [-t time] [-s time|-f factor] command

niceload [-v] [-n nice] [-l load] [-t time] [-s time|-f factor] -p=PID

DESCRIPTION

GNU niceload will run a program when the load average is below 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 load average is checked again and we start over.

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, ...

OPTIONS

-n niceness: Sets niceness. See nice(1).
-l maxload: Max load. The maximal load average before suspending command. Default is 1.00.
-t SEC: Recheck load time. Sleep SEC seconds before checking load again. Default is 1 second.
-s SEC: Suspend time. Suspend the command this many seconds when the max load average is reached.
-f FACTOR: Suspend time factor. Dynamically set -s as max load average over limit * factor. Default is 1.
-p PID: Process ID of process to suspend.
-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 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 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/

ENVIRONMENT VARIABLES

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

EXIT STATUS

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

REPORTING BUGS

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

AUTHOR

LICENSE

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/>.

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:

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

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.

DEPENDENCIES

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