niceload - slow down a program when the load average is above a certain limit
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
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, ...
Sets niceness. See nice(1).
Max load. The maximal load average before suspending command. Default is 1.00.
Recheck load time. Sleep SEC seconds before checking load again. Default is 1 second.
Suspend time. Suspend the command this many seconds when the max load average is reached.
Suspend time factor. Dynamically set -s as max load average over limit * factor. Default is 1.
Process ID of process to suspend.
Verbose. Print some extra output on what is happening. Use -v until you know what your are doing.
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.
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
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/
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 <bug-parallel@gnu.org>.
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.
Copyright (C) 2010 Free Software Foundation, Inc.
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GNU niceload uses Perl, and the Perl modules POSIX, and Getopt::Long.
parallel(1), nice(1)