CPUID(8)                                                 CPUID(8)

     NAME
          cpuid - x86 cpuid instriction

     SYNOPSIS
          cpuid [ -w mach ] [-efisvt] [-n fn]

     DESCRIPTION
          Cpuid prints out information gleaned from the Intel CPUID
          instruction.  A function number may be specified with the -n
          flag.  Alternatively, a few known functions are available

          -e    decode extended feature information from function
                0x80000001.

          -f    decode feature information from function 1.

          -i    print the informational brand string gathered from
                functions 0x80000002-6.

          -s    print the processor signature returned in AX from
                function 0x01 in raw form and also as
                family.model.stepping.

          -v    print the manufacturer's identification string
                returned by function 0x00.

          -t    Intel only?  print the X2APIC processor topology.

          EXAMPLE

               chula; aux/cpuid -t
               thread    00000001 00000002 00000100 00000000
               core      00000004 00000008 00000201 00000000
               mach0     apic 00000000
               mach1     apic 00000002
               mach2     apic 00000004
               mach3     apic 00000006
               4 machs inactive

     SOURCE
          /sys/src/cmd/aux/cpuid

     BUGS
          Functions are architecture and vendor specific.

     Page 1                       Plan 9            (printed 12/22/25)