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 a VAX 6000 system or 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/I64 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/I64 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/I64 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

$ STOP/CPU 
      

The STOP/CPU command in this example selects a processor and removes it from the multiprocessing system's active set.

$ STOP/CPU 4,7
      

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.

$ 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.

$ STOP/CPU/ALL
      

The STOP/CPU/ALL command in this example stops all eligible secondary processors in the active set and removes them from the multiprocessing system.

$ 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.

$ 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.