COMMAND RELATED TO CPU ON SOLARIS 10

Number of Physical processors#
psrinfo -p

Numbers of cores
# kstat cpu_info | grep core_id | uniq | wc -l

Number of Virtual Processors on each of these Physical processors (core x threads)
# psrinfo -pv

For example

# psrinfo -p
   8
# kstat cpu_info | grep core_id | uniq | wc -l
   32

# psrinfo -pv
The physical processor has 8 virtual processors (0-7)
  SPARC64-VII (portid 1024 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (8-15)
  SPARC64-VII (portid 1032 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (16-23)
  SPARC64-VII (portid 1040 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (24-31)
  SPARC64-VII (portid 1048 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (32-39)
  SPARC64-VII (portid 1056 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (40-47)
  SPARC64-VII (portid 1064 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (48-55)
  SPARC64-VII (portid 1072 impl 0x7 ver 0xa1 clock 2530 MHz)
The physical processor has 8 virtual processors (56-63)
  SPARC64-VII (portid 1080 impl 0x7 ver 0xa1 clock 2530 MHz)

It means there are :
- 8 physical processors
- 32 cores (4 in each physical processors)  
- 64 virtual processors (2 in each cores)

Take the specified virtual processors off-line
# psradm -f  1 2 3 5 6 7

Where 1, 2, 3, 5, 6, 7 like virtual processor id (you can check this with psrinfo -v) 

Bring the specified virtual processors on-line
# psradm -n  0 4
Where 0 and 4 like virtual processor id (you can check this with psrinfo -v) 

Check status of virtual processors
# psrinfo -v