dispadmin(ADM)

dispadmin -- process scheduler administration

Synopsis

dispadmin -l

dispadmin -c class -g [-r res]

dispadmin -c class -s file

Description

The dispadmin command displays or changes process scheduler parameters while the system is running.

The -l option lists the scheduler classes currently configured in the system.

The -c option specifies the class whose parameters are to be displayed or changed.

The -g option gets the parameters for the specified class and writes them to the standard output. Parameters for the time-sharing class are described on ts_dptbl(F), parameters for the fixed priority class are described on fp_dptbl(F), and parameters for the fixed class are described on fc_dptbl(F).

When using the -g option you may also use the -r option to specify a resolution to be used for outputting the time quantum values. If no resolution is specified, time quantum values are in milliseconds. If res is specified it must be a positive integer between 1 and 1000000000 inclusive, and the resolution used is the reciprocal of res in seconds. For example, a res value of 10 yields time quantum values expressed in tenths of a second; a res value of 1000000 yields time quantum values expressed in microseconds. If the time quantum cannot be expressed as an integer in the specified resolution, it is rounded up to the next integral multiple of the specified resolution.

The -s option sets scheduler parameters for the specified class using the values in file. These values overwrite the current values in memory--they become the parameters that control scheduling of processes in the specified class. The values in file must be in the format output by the -g option. Moreover, the values must describe a table that is the same size (has same number of priority levels) as the table being overwritten. Appropriate privileges are required in order to use the -s option.

The -g and -s options are mutually exclusive: you may not retrieve the table at the same time you are overwriting it.

dispadmin does some limited sanity checking on the values supplied in file to verify that they are within their required bounds. The sanity checking, however, does not attempt to analyze the effect that the new values have on the performance of the system. Inappropriate values can have a dramatic negative effect on system performance.

Examples

The following command retrieves the current scheduler parameters for the fixed priority class from kernel memory and writes them to the standard output. Time quantum values are in microseconds.

dispadmin -c FP -g -r 1000000

To overwrite the current scheduler parameters for the fixed priority class with the values specified in fp.config, ienter:

dispadmin -c FP -s fp.config

The following command retrieves the current scheduler parameters for the time-sharing class from kernel memory and writes them to the standard output. Time quantum values are in nanoseconds.

dispadmin -c TS -g -r 1000000000

To overwrite the current scheduler parameters for the time-sharing class with the values specified in ts.config, enter:

dispadmin -c TS -s ts.config

Diagnostics

dispadmin prints an appropriate diagnostic message if it fails to overwrite the current scheduler parameters due to lack of required permissions or a problem with the specified input file.

References

fc_dptbl(F), fp_dptbl(F), priocntl(C), priocntl(S), ts_dptbl(F)