CPUCTL(8)               NetBSD System Manager's Manual               CPUCTL(8)

     cpuctl -- program to control CPUs

     cpuctl [-v] command [arguments]

     The cpuctl command can be used to control and inspect the state of CPUs
     in the system.

     The first argument, command, specifies the action to take.  Valid com-
     mands are:

     identify cpu [cpu ...]
               Output information on the specified CPU's features and capabil-
               ities.  Not available on all architectures.

     list      For each CPU in the system, display the current state and time
               of the last state change.

     offline cpu [cpu ...]
               Set the specified CPUs off line.

               Unbound LWPs (lightweight processes) will not be executed on a
               CPU while it is off line.  Bound LWPs will continue to be exe-
               cuted on the CPUs, and device interrupts routed to the CPUs
               will continue to be handled.  A future release of the system
               may allow device interrupts to be re-routed away from individ-
               ual CPUs.

               At least one CPU in the system must remain on line.

     online cpu [cpu ...]
               Set the specified CPUs on line, making them available to run
               unbound LWPs.

     ucode [cpu] [file]
               This applies the microcode patch to CPUs.  If cpu is not speci-
               fied or -1, all CPUs are updated.  If cpu is -2, the current
               CPUs are updated.  The default filename is used if no filename
               is specified.  The identify command prints the installed ver-
               sion on the specified CPUs.  On success the identify command
               shows different ucode versions before and after this command.
               The ucode updates are found in the default firmware path found
               in sysctl hw.firmware.path.

     intr cpu [cpu ...]
               Enable interrupts for the specified CPUs if supported.

     nointr cpu [cpu ...]
               Disable interrupts for the specified CPUs if supported.

     Valid flags are:

     -v      Be more verbose.

     /dev/cpuctl  control device
                  The directory to install the microcode file for AMD CPUs
                  into.  The default filename is microcode_amd.bin for CPU
                  families 0x10 to 0x14.  The default filename is
                  microcode_amd_famXXh.bin where XX is the CPU family starting
                  with 15 (hex).  Get it from

           cpuctl identify 0
     and you should see something like this:

           cpu0: UCode version: 0x1000080

     After applying the microcode patch with
           cpuctl ucode 0
     you can see with
           cpuctl identify 0
     that the patch got applied:

           cpu0: UCode version: 0x1000083

     intrctl(8), psrset(8), schedctl(8), sysctl(8), firmload(9)

     The cpuctl command first appeared in NetBSD 5.0.

NetBSD 9.0                       May 17, 2019                       NetBSD 9.0

You can also request any man page by name and (optionally) by section:


Use the DEFAULT collection to view manual pages for third-party software.

©1994 Man-cgi 1.15, Panagiotis Christias
©1996-2019 Modified for NetBSD by Kimmo Suominen