NAME

       reniced - renice running processes based on regular expressions

SYNOPSIS

       reniced [-h] [-v] [-o format] [configfile]

OVERVIEW

       reniced takes a list of regular expressions, looks for processes (and threads) matching them and renices
       the processes to given values.  reniced can also change io priorities.

DESCRIPTION

       On start, reniced reads a configuration file.  It consists of nice values and regular expressions.

       It then scans the process table using the ps(1) command.  Whenever a process name from the CMD column
       matches a regular expression, that process is reniced to the given value.  If a process matches multiple
       regular expressions, all rule matches are executed in order and the last match wins.

       When run as root, reniced will scan all processes ("`ps H -e`").  When run as a user, renice only scans
       the user's processes ("`ps H --user`").

   Switches
       -h   This prints the version number, a short help text and exits without doing anything.

       -v   This activates verbose mode.  Error messages, some statistics and all renice actions are printed to
            stdout.

       -o format
            Set the ps(1) output format to filter on.  The default format is "comm".  See the -o parameter in
            the ps(1) manpage for details.

       configfile
            This reads the regular expressions from an alternate configfile.

            The default location of the configfile is "/etc/reniced.conf" if reniced is run as root,
            "~/.reniced" otherwise.

   Configuration file format
       The configuration file is composed of single lines.  Empty lines and lines starting with a # are ignored.

       Every line must consist of a command followed by a whitespace and a Perl regular expression.

       The regular expression is matched against the ps(1) output.  For every matched process the command is
       executed.

       A command generally takes the form of a character followed by a number.  Multiple commands can be given
       simultaneously with no spaces inbetween.  Sometimes the number is optional.

       Command characters

       n    Sets the nice value of a process.  Must be followed by a number, usually within the range of -20 to
            19.

            For backwards compatibility a n at the beginning of the command can be left out (if the command
            starts with a number it is treated as a nice value).

       r    Sets the io priority to the realtime scheduling class.  The optional number is treated as class data
            (typically 0-7, lower being higher priority).

       b    Sets the io priority to the best-effort scheduling class.  The optional number is treated as class
            data (typically 0-7, lower being higher priority).

       i    Sets the io priority to the idle scheduling class.  No number needs to be given as the idle
            scheduling class ignores the class data value.

       o    Sets the OOM killer adjustment in "/proc/$PID/oom_adj" to the given number.  (Internally,
            "/proc/$PID/oom_score_adj" will be used when available, but for backwards compatibility this value
            is still expected the in old "oom_adj" format and will be converted automatically.)

       Examples

       "5 ^bash"
            gives currently running bash shells a nice value of 5

       "b2 ^tar"
            sets currently running tar-processes to io priority best-effort within class 2

       "i torrent"
            sets currently running torrent-like applications to io priority idle

       "n-10r4 seti"
            gives currently running seti-processes a nice value of -10 and sets them to realtime io priority in
            class 4

MODULES NEEDED

        use BSD::Resource;

       This module can be obtained from <http://www.cpan.org>.

PROGRAMS NEEDED

        ps
        ionice

       ionice is only needed if you want to change io priority.  It can be obtained from
       <http://rlove.org/schedutils/>.

       You also need a suitable kernel and scheduler, e.g. Linux 2.6 with CFQ.

LIMITATIONS

       The purpose of reniced is to renice long running server processes (hence the d for daemon in it's name).

       Selecting and renicing processes it not atomic: There is a small gap between scanning the process list
       and renicing the processes.  If you target short-lived processes with your regular expressions, reniced
       might try to act on a process that is already gone.  In the worst case it might renice a new process that
       got the same process id as the already ended process that was matched.

BUGS

       reniced can run without the BSD::Resource module.  In this case, the PRIO_PROCESS is set to 0.  This
       works on Linux 2.6.11 i686 but it could break on other systems.  Installing BSD::Resource is the safer
       way.

       Be careful using realtime priorities, don't starve other tasks.

       Please report bugs to <mitch@cgarbs.de>.

AUTHOR

       reniced was written by Christian Garbs <mitch@cgarbs.de>.

COPYRIGHT

       reniced is Copyright (C) 2005 by Christian Garbs.  It is licensed under the GNU GPL v2 or later.

AVAILABILITY

       Look for updates at <https://github.com/mmitch/reniced>.

SEE ALSO

       ionice(1), renice(1), ps(1)