DISPADMIN(8) Maintenance Commands and Procedures DISPADMIN(8)

NAME

dispadmin - process scheduler administration

SYNOPSIS

dispadmin -l


dispadmin -c class {-g [-r res] | -s file}


dispadmin -d [class]

DESCRIPTION

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


dispadmin does limited checking on the values supplied in file to verify
that they are within their required bounds. The 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 negative
effect on system performance. (See System Administration Guide: Advanced
Administration.)

OPTIONS

The following options are supported:

-c class

Specifies the class whose parameters are to be displayed or changed.
Valid class values are: RT for the real-time class, TS for the time-
sharing class, IA for the inter-active class, FSS for the fair-share
class, and FX for the fixed-priority class. The time-sharing and
inter-active classes share the same scheduler, so changes to the
scheduling parameters of one will change those of the other.


-d [class]

Sets or displays the name of the default scheduling class to be used
on reboot when starting svc:/system/scheduler:default. If class name
is not specified, the name and description of the current default
scheduling class is displayed. If class name is specified and is a
valid scheduling class name, then it is saved in dispadmin's private
configuration file /etc/dispadmin.conf. Only super-users can set the
default scheduling class.


-g

Gets the parameters for the specified class and writes them to the
standard output. Parameters for the real-time class are described in
rt_dptbl(5). Parameters for the time-sharing and inter-active
classes are described in ts_dptbl(5). Parameters for the fair-share
class are described in FSS(4). Parameters for the fixed-priority
class are described in fx_dptbl(5).

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


-l

Lists the scheduler classes currently configured in the system.


-r res

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.


-s file

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. Super-user privileges are required in order to use the
-s option.

Time quantum values for scheduling classes are specified in system
clock ticks rather than constant-time units. These values are based
on the value of the kernel's hz variable. By default, the system
operates at 1000 Hz and thus with a quantum of 1 millisecond. If the
kernel tunable hires_tick is set to 0, this drops to 100 Hz for a
larger quantum of 10 milliseconds.

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

EXAMPLES

Example 1: Retrieving the Current Scheduler Parameters for the real-time

class


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


dispadmin -c RT -g -r 1000000

Example 2: Overwriting the Current Scheduler Parameters for the Real-time

Class


The following command overwrites the current scheduler parameters for the
real-time class with the values specified in rt.config.


dispadmin -c RT -s rt.config

Example 3: Retrieving the Current Scheduler Parameters for the Time-

sharing Class


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

Example 4: Overwriting the Current Scheduler Parameters for the Time-

sharing Class


The following command overwrites the current scheduler parameters for the
time-sharing class with the values specified in ts.config.


dispadmin -c TS -s ts.config

FILES

/etc/dispadmin.conf

Possible location for argument to -s option.

SEE ALSO

priocntl(1), svcs(1), priocntl(2), FSS(4), fx_dptbl(5), rt_dptbl(5),
ts_dptbl(5), attributes(7), smf(7), svcadm(8)

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.

NOTES

The default scheduling class setting facility is managed by the service
management facility, smf(7), under the service identifier:

svc:/system/scheduler:default


Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using svcadm(8). Note that disabling
the service while it is running will not change anything. The service's
status can be queried using the svcs(1) command.

October 7, 2008 DISPADMIN(8)