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)