Sunday, August 9, 2009

Start and Stop CPU in OpenVMS

Yes, Its not a dream!!! .
You can start or stop a particular Processor in multiprocessor server.If you don't want to involve all of the available processors for the current tasks running in the system, just stop the unwanted CPU. Then server will remove the stopped CPU from active CPU database. This feature will help an organization to reduce much of the power conception by CPU usage.
Currently this feature available only on OpenVMS Operating system running on VAX/Alpha or I64 machines. below are the commands to manage the CPUS.

1.
$ show cpu/full

2.$ stop/cpu 2 // this command will stop a CPU of id 2. This id can be see from executing 'show cpu/full command'

3.
$ start/cpu 2 // This command will start the stopped CPU of id 2.

More details :

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.

Examples :


$ stop/cpu 2

//Will stop the CPU 2 and State of the CPU will be shown as STOPPED. See the out for the below command. The CPU 2 states is in STOPPED now. All the running CPUs will be in RUN state

$ show cpu/full

System: , HP rx4640 (1.30GHz/3.0MB)

SMP execlet = 3 : Enabled : Streamlined.
Config tree = Version 6
Primary CPU = 0
HWRPB CPUs = 4
Page Size = 8192
Revision Code =
Serial Number = USE44136MR
Default CPU Capabilities:
System: QUORUM RUN
Default Process Capabilities:
System: QUORUM RUN

CPU 0 State: RUN CPUDB: 89020000 Handle: 00005D70
Owner: 000004C8 Current: 000004C8 Partition 0 ()
ChgCnt: 1 State: Present, Primary, Reassignable
Process: SYSTEM PID: 2440042E
Capabilities:
System: PRIMARY QUORUM RUN RAD0
Slot Context: 92B95000
CPU - State..........: RC, PA, PP, CV, PV, PMV, PL
Type...........: Itanium Major = 31, Minor = 1
Speed..........: 1300 Mhz
LID............: 00000000
Variation......: IEEE FP, Primary Eligible
Serial Number..: e52e8e9c01b90000
Revision.......:
Halt Request...: 0
Software Comp..: 5.0
PALCODE - Revision Code..: 1.1
Compatibility..: 0
Max Shared CPUs: 0
Bindings: * None *
Fastpath:
PKD0
PKC0
PEA0
Features:
Autostart - Enabled.
Fastpath - Selection enabled as Preferred CPU.

CPU 1 State: STOPPED CPUDB: 8917AF00 Handle: 00005E80
Owner: 000004C8 Current: 000004C8 Partition 0 ()
ChgCnt: 2 State: Present, In-Console, Reassignable
Process: * None *
Capabilities:
System: QUORUM RAD0
Slot Context: 92B96000
CPU - State..........: BIP, PA, PP, CV, PV, PMV, PL
Type...........: Itanium Major = 31, Minor = 1
Speed..........: 1300 Mhz
LID............: 01000000
Variation......: IEEE FP
Serial Number..: d566f80703b90100
Revision.......:
Halt Request...: 4
Software Comp..: 5.0
PALCODE - Revision Code..: 1.1
Compatibility..: 0
Max Shared CPUs: 0
Bindings: * None *
Fastpath: * None *
Features:
Autostart - Enabled.
Fastpath - Selection enabled as Preferred CPU.

CPU 2 State: STOPPED CPUDB: 8917CD00 Handle: 00005F90
Owner: 000004C8 Current: 000004C8 Partition 0 ()
ChgCnt: 2 State: Present, In-Console, Reassignable
Process: * None *
Capabilities:
System: QUORUM RAD0
Slot Context: 92B97000
CPU - State..........: BIP, PA, PP, CV, PV, PMV, PL
Type...........: Itanium Major = 31, Minor = 1
Speed..........: 1300 Mhz
LID............: 02000000
Variation......: IEEE FP
Serial Number..: a11db90f8ddd0000
Revision.......:
Halt Request...: 4
Software Comp..: 5.0
PALCODE - Revision Code..: 1.1
Compatibility..: 0
Max Shared CPUs: 0
Bindings: * None *
Fastpath: * None *
Features:
Autostart - Enabled.
Fastpath - Selection enabled as Preferred CPU.

CPU 3 State: RUN CPUDB: 8917EC80 Handle: 000060A0
Owner: 000004C8 Current: 000004C8 Partition 0 (
)
ChgCnt: 1 State: Present, Reassignable
Process: * None *
Capabilities:
System: QUORUM RUN RAD0
Slot Context: 92B98000
CPU - State..........: RC, PA, PP, CV, PV, PMV, PL
Type...........: Itanium Major = 31, Minor = 1
Speed..........: 1300 Mhz
LID............: 03000000
Variation......: IEEE FP
Serial Number..: 87eae30f7f950300
Revision.......:
Halt Request...: 0
Software Comp..: 5.0
PALCODE - Revision Code..: 1.1
Compatibility..: 0
Max Shared CPUs: 0
Bindings: * None *
Fastpath:
EWA0
BG0
EWB0
Features:
Autostart - Enabled.
Fastpath - Selection enabled as Preferred CPU.



$ start/cpu 2

//Will start the CPU 2




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