HP OpenVMS DCL Dictionary
STOP/CPU
Stops the specified secondary processor or processors (and any
associated vector processors). The /CPU qualifier is required.
Applies only to OpenVMS multiprocessing systems. Requires
CMKRNL (change mode to kernel) privilege.
Format
STOP/CPU [cpu-id[,...]]
Parameter
cpu-id[,...]
Specifies a decimal value representing the identity of a processor in
an OpenVMS multiprocessing system. On an Alpha 7000 system, the CPU ID
is the backplane slot number of the processor. If you do not specify a
CPU ID, the STOP/CPU command selects a processor in the current active
set to stop.
Description
The STOP/CPU command removes a secondary processor from the active set
in an OpenVMS multiprocessing system. If the secondary processor is not
executing a process when the STOP/CPU command is issued, it enters the
STOPPED state. If the secondary is executing a process at the time, it
continues to execute the current process until it attempts to schedule
another process. When this occurs, the secondary enters the STOPPED
state.
The OpenVMS operating system subjects a processor to a set of checks
when it is the object of a STOP/CPU command. As a result, you may not
be permitted to stop certain processors that are vital to the
functioning of the system. In these cases, there is usually a process
in the system that can execute only on the processor you intend to
stop. You can determine this by issuing a SHOW CPU/FULL command. In
unusual circumstances, you can bypass the checking mechanism by using
the /OVERRIDE_CHECKS qualifier in the command.
The STOP/CPU command has no effect if its object processor is already
in the STOPPED state when it is issued.
Qualifiers
/ALL
Stops all eligible secondary processors in the system's active set.
/ASSIGN=option (Alpha/Integrity servers only)
Assigns specified processors to the hard partition node after they are
stopped.
| Option |
Description |
|
$$HARD_PARTITION
|
The configuration tree hard partition node. All instances running in
the hard partition defined by this node have visibility and access to
CPUs owned at this level.
|
Supported only on AlphaServer systems that support partitioning.
/MIGRATE (Alpha/Integrity servers only)
Transfers ownership of the CPU from the current instance to another
soft partition.
| Option |
Description |
|
instance_name
|
The name of any valid running instance in the current hard partition.
|
|
partitionID
|
The numeric ID of any partition (reflected in the configuration tree)
in the current hard partition. An operating system instance is not
required to be running with this identifier.
|
Supported only on AlphaServer systems that support partitioning.
/OVERRIDE_CHECKS
Directs the STOP/CPU command to bypass a series of OpenVMS scheduling
checks that determine whether the specified processor is eligible for
removal from the active set.
Note that this is not an unconditional operation; other CPU load or
configuration constraints may prevent the specified processor from
being stopped.
/POWER=OFF (Alpha/Integrity servers only)
Powers down the CPU after it is removed from the active set. The CPU
will be powered down while still owned by the instance, prior to any
assignments.
The /POWER qualifier cannot be used in conjunction with the /MIGRATE
qualifier.
Supported only on AlphaServer GS series systems.
Examples
The STOP/CPU command in this example selects a processor and removes it
from the multiprocessing system's active set.
The STOP/CPU command in this example selects the processors with CPU
IDs 4 and 7 and removes them from the multiprocessing system's active
set.
| #3 |
$ STOP/CPU/OVERRIDE_CHECKS 8
|
The STOP/CPU/OVERRIDE_CHECKS command in this example overrides some
OpenVMS scheduling states that ordinarily prevent the operation and
stops the processor with the CPU ID of 8. Then it is removed from
active participation in the multiprocessing system.
The STOP/CPU/ALL command in this example stops all eligible secondary
processors in the active set and removes them from the multiprocessing
system.
| #5 |
$ STOP/CPU/MIGRATE=WFGLXE 5
|
The STOP/CPU/MIGRATE command in this example removes CPU 5 from the
current instance's active set and transfers ownership to instance
WFGLXE in the current hard partition.
| #6 |
$ STOP/CPU/ASSIGN=$$HARD 6
|
The STOP/CPU/MIGRATE command in this example removes CPU 6 from the
current instance's active set and transfers ownership to the hard
partition node in the configuration tree. The CPU is immediately
available for assignment for any instance within the hard partition
defined by that node.
| 
