Go to main content

man pages section 8: System Administration Commands

Exit Print View

Updated: Wednesday, February 9, 2022



psrinfo - displays information about processors


psrinfo [-p] [-v] [processor_id]...
psrinfo [-p] -s processor_id
psrinfo -t [-L]


psrinfo displays information about processors. Each physical processor may support multiple virtual processors. Each virtual processor is an entity with its own interrupt ID, capable of executing independent threads.

Without the processor_id operand, psrinfo displays one line for each configured processor, displaying whether it is on-line, non-interruptible (designated by no-intr), spare, off-line, faulted or powered off, and when that status last changed. Use the processor_id operand to display information about a specific processor. See OPERANDS.


The following options are supported:

–s processor_id

Silent mode. Displays 1 if the specified processor is fully on-line. Displays 0 if the specified processor is non-interruptible, spare, off-line, faulted or powered off.

Use silent mode when using psrinfo in shell scripts.


Display the number of physical processors in a system.

When combined with the –v option, reports additional information about the physical layout of the physical processor. The additional information also gives which virtual CPUs are contained in a processor socket or core. Typically, a physical processor plugs into a socket and socket is often used to refer to a physical processor. Each physical processor usually contains some number of cores which each contain one or more virtual CPUs that can each execute instructions.

These physical groupings of virtual CPUs may have some performance relevant shared hardware components such as execution pipeline, FPU, cache, or pipe to memory. However, these performance relevant shared hardware components may not necessarily be inferred across different physical processors. Also, one cannot necessarily infer which CPUs are in a Non Uniform Memory Access (NUMA) node from physical groupings. To see the NUMA configuration, refer to the lgrpinfo(1) man page. For more information, see the pginfo(8) man page.


Verbose mode. Displays additional information about the specified processors, including: processor type, floating point unit type and clock speed. If any of this information cannot be determined, psrinfo displays unknown.

When combined with the –p option, reports additional information about each physical processor.


Tree mode. Displays a tree of the system's processors and their associated socket, core, and cpu ids.


Locality group mode. Annotates output with lgroup membership information. Must be used with –t option.


The following operands are supported:


The processor ID of the processor about which information is to be displayed.

Specify processor_id as an individual processor number (for example, 3), multiple processor numbers separated by spaces (for example, 1 2 3), or a range of processor numbers (for example, 1-4). It is also possible to combine ranges and (individual or multiple) processor_ids (for example, 1‐3 5 7‐8 9).


Example 1 Displaying Information About All Configured Processors in Verbose Mode

The following example displays information about all configured processors in verbose mode.

psrinfo –v 
Example 2 Determining If a Processor is On-line

The following example uses psrinfo in a shell script to determine if a processor is on-line.

if [ "`psrinfo –s 3 2> /dev/null`" −eq 1 ]
	echo "processor 3 is up"
Example 3 Displaying Information About the Physical Processors in the System

With no additional arguments, the –p option displays a single integer: the number of physical processors in the system:

> psrinfo -p

psrinfo also accepts command line arguments (processor IDs):

> psrinfo -p 0 512   # IDs 0 and 512 exist on the 
1                    # same physical processor

> psrinfo -p 0 1     # IDs 0 and 1 exist on different 
2                    # physical processors

In this example, virtual processors 0 and 512 exist on the same physical processor. Virtual processors 0 and 1 do not. This is specific to this example and is and not a general rule.

Exit Status

The following exit values are returned:


Successful completion.


An error occurred.


See attributes(7) for descriptions of the following attributes:


See Also

lgrpinfo(1), p_online(2), processor_info(2), attributes(7), psradm(8), pginfo(8)


psrinfo: processor 9: Invalid argument

The specified processor does not exist.