Installation guide

• Execute class scheduling commands from within scripts using the

command line version of class_admin.

4.7.2 Utilities Related to Class Scheduling

The following utilities are also available for use when monitoring and

tuning processes:

• The nice and renice commands

• The iostat and vmstat commands

• The Process Tuner (dxproctuner) graphical interface, available from

the CDE MonitoringTuning folder in the Application Manager -

System_Admin. Refer to the online help for more information on using

this interface.

Refer also to the

System Conﬁguration and Tuning guide for more

information on tuning options.

4.7.3 Planning Class Scheduling

How you allocate CPU resources will depend on your system environment

and what resources and priorities must be considered. A typical scenario is

to assign a higher CPU percentage to interactive tasks so that users do not

encounter long response times. Most batch or background processes will be

assigned a lower CPU percentage, while some speciﬁc background

processes may require a higher CPU percentage. For example, if a nightly

back up is being performed, you might not want it to have such a low CPU

percentage that it does not complete in a reasonable time. Alternatively, if

there are critical real-time tasks that should take precedence over

interactive processes such as process control applications, you may want to

assign more resources to real-time tasks. Compaq recommends that you

design a baseline, assigning processes to classes and then monitor

processes and user feedback to tune the database by moving tasks from

class to class or changing the CPU access time of the classes.

4.7.4 Conﬁguring Class Scheduling

Use the class_admin command to conﬁgure an initial database. This

command provides:

• An interactive command with sub commands that enable you to create

and administer a database of classes. The database is stored in the

binary ﬁle /etc/class, which cannot be edited manually. Type help

at the class> command prompt for a list of options.

• A command mode that allows you to execute class_admin commands

at the command prompt, or include commands in shell scripts.

Customizing the System Environment 4–29