The psradm utility changes the operational status of processors. The legal states for the processor are on-line, off-line, and no-intr.
An on-line processor processes LWPs (lightweight processes) and may be interrupted by I/O devices in the system.
An off-line processor does not process any LWPs. Usually, an off-line processor is not interruptible by I/O devices in the system.
On some processors or under certain conditions, it may not be possible to disable interrupts for an off-line processor. Thus, the actual effect of being off-line may
vary from machine to machine.
A no-intr processor processes LWPs but is not interruptible by I/O devices.
A processor may not be taken off-line if there are LWPs that are bound to the processor. On some architectures, it might not be possible to take certain processors off-line if, for example, the system depends on some resource provided by the processor.
At least one processor in the system must be able to process LWPs. At least one processor must also be able to be interrupted. Since an off-line
processor may be interruptible, it is possible to have an operational system with one processor no-intr and all other processors off-line but with one or more accepting
interrupts.
If any of the specified processors are powered off, psradm may power on one or more processors.
Only superusers can use the psradm utility.
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