Open System Services Management and Operations Guide (G06.30+, H06.08+, J06.03+)

Using the nice Command

The nice command lets you start an OSS process at a modified priority. All users can lower the

execution priority of a process, but only the super ID can increase the execution priority of a

process.

Priority values in a traditional UNIX system have a significance opposite that of the values used

on a NonStop server. For a description of the relationship among the nice value of a process,

the OSS scheduling priority for the process, and the Guardian priority for the process, see the

run(1), nice(1), and nice(2) reference pages either online or in the Open System Services

Shell and Utilities Reference Manual and Open System Services System Calls Reference Manual.

You can use the nice command to adjust the response time of servers that run in the OSS

environment. For example, to start the inetd process at a priority slightly higher than the default

priority, enter:

nice -n -1 /usr/ucb/inetd

To specify a lower priority for the inetd process, enter:

nice -n 15 /usr/ucb/inetd

This command executes the inetd process and decreases the priority by 15, which is a priority

even lower than the default priority set by nice.

Using an OSS Shell Script

Unlike a shell alias, the shell script method works for calls to a program from within another shell

script. To use an OSS shell script that changes the default priority of a program, follow these steps:

NOTE: Using shell scripts increases system overhead. Be sure that the performance tradeoff is

worthwhile before you use this technique.

• Create a script file that has the same name as the program for which you want to change the

default priority. Put the following information in the script file:

#! /bin/sh

nice -n nn program_name

is the priority adjustment for the process.

program_name

is the name of the program to be executed.

1. Place the script file in a special directory you control. Secure the file so that it can be executed

by everyone but not altered by anyone.

2. Add your special directory to the PATH environment variable used to find program files. You

need to do this only the first time you create such a script, provided you always use the same

OSS directory.

Most users use the PATH definition in /etc/profile, so change that file such that your

special directory is searched first.

3. Notify those users that have their own .profile file or otherwise alter the PATH variable

about what you are doing so that they can make comparable changes to their definitions of

PATH.

For example, to run a program called logout that is normally stored in /usr/bin with a priority