How to Tune Scheduler Parameters

You can use the dispadmin command to display or change process scheduler parameters while the system is running. For example, you can use dispadmin to examine and tune the FSS scheduler's time quantum value. Time quantum is the amount of time that a thread is allowed to run before it must relinquish the processor.

To display the current time quantum for the FSS scheduler while the system is running, type:

$ dispadmin -c FSS -g
#
# Fair Share Scheduler Configuration
#
RES=1000
#
# Time Quantum
#
QUANTUM=110

When you use the -g option, you can also use the -r option to specify the resolution that is used for printing time quantum values. If no resolution is specified, time quantum values are displayed in milliseconds by default.

$ dispadmin -c FSS -g -r 100
#
# Fair Share Scheduler Configuration
#
RES=100
#
# Time Quantum
#
QUANTUM=11

To set scheduling parameters for the FSS scheduling class, use dispadmin -s. The values in file must be in the format output by the -g option. These values overwrite the current values in the kernel. Type the following:

$ dispadmin -c FSS -s file