psradm, offline, online - Stops and starts processors in a
/usr/sbin/psradm -f [-v] [[-a] [processor_id...]]
/usr/sbin/psradm -n [-v] [[-a] [processor_id...]]
/usr/sbin/online [-v] [processor_id...]
/usr/sbin/offline [-v] [processor_id...]
The following options apply only to the psradm command:
Specifies that all the processors except the master processor
be put off line or on line. Puts the specified
processor off line. Puts the specified processor on line.
The following option applies to all forms of the command:
Displays a message about the status of the operation performed
on each processor.
On a multiprocessor system, the psradm command puts one or
more processors off line (stops a processor) or on line
(starts a processor).
The processor_id variable specifies an integer that
uniquely identifies a processor. Use the psrinfo command
to display processor identification numbers.
The offline command puts one or more processors off line
(stops a processor). If no processors are specified, all
processors that are on line are stopped except the master
The online command puts one or more processors on line
(starts a processor). If no processors are specified, all
processors that are off line are started.
You must be the root user to use this command.
The /var/adm/wtmp file contains information about successful
processor state transitions.
Do not use the psradm command to disable CPUs when benchmarking
performance, because the command does not provide
an accurate reflection of the performance of a system that
actually has fewer CPUs. Accurate performance results are
obtained only when you disable the CPUs at the SRM console
On platforms that do not support primary processor reassignment,
you cannot use the off line command options to
stop the boot processor in a multiprocessor system.
Each quad building block (QBB) on a AlphaServer GS-series
system assigns one processor to take interrupts for that
QBB. If you attempt to take this processor off line, the
following error is displayed: offline: processor N:
An interrupt-handling processor has an identifier number
(N) that is evenly divisibe by 4. At present, there is no
method of migrating interrupts to another processor,
therefore, you cannot take this processor off line.
The following command puts processors 2 and 3 off line: #
psradm -f 2 3 The following command puts all the processors
on line: # psradm -n -a The following command puts
all processors on line: # online -v
Commands: pset_info(1), psrinfo(1)
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