Index for Section 3

Alphabetical listing for C

Bottom of page

cpu_get_info(3)
NAME
  cpu_get_info, cpu_get_num, cpu_get_max - Query CPU information for the
  platform (libc library)

SYNOPSIS
  #include <cpuset.h>

  int cpu_get_info(
	  ncpu_info_t *info );

  int cpu_get_num(
	  void );

  int cpu_get_max(
	  void );

PARAMETERS
  info
      Points to an ncpu_info_t buffer to receive the CPU information for the
      booted configuration.

DESCRIPTION
  The cpu_get_info() function returns the following information about the
  platform CPU configuration in the buffer pointed to by the info parameter:

  int ncpu_version
      Revision number.

  int ncpu_max
      Maximum number of CPUs supported by the machine architecture.

  cpuset_t ncpu_present
      CPU processor set that is physically plugged into the system and
      recognized by the system console.

  cpuset_t ncpu_running
      Set of online CPUs in the caller's partition; that is, the set of CPUs
      on which the caller can schedule work.

  cpuset_t ncpu_binding
      Set of CPUs in the partition that have processes bound to them.

  cpuset_t ncpu_ex_binding
      Set of CPUs in the partition whose processor set is marked for
      exclusive use.

  The CPU sets specified in the ncpu_info_t structure must have been created
  by the caller prior to the call.  If the caller specifies zero for a CPU
  set, the function silently ignores filling in data for that set.

  The information returned by the cpu_get_info() function is relative to the
  caller's partition.

  The cpu_get_num() function returns the actual number of CPUs available in
  the caller's partition.

  The cpu_get_max() function returns the maximum number of CPUs, including
  unpopulated CPU slots, that can be configured in the system.

NOTES
  A cpu_get_info() call is similar to a getsysinfo(GSI_CPU_INFO, ...) call.
  The principal difference is that the	main ncpu_info_t structure fields
  returned by cpu_get_info() are of type cpuset_t, whereas the same
  information returned by getsysinfo()is of type ulong_t.  Furthermore, a
  getsysinfo(GSI_CPU_INFO, ...) call returns information only about the first
  n CPUs, where n is the number of bits in a ulong_t field, or
  (sizeof(ulong_t)*8).

  For cpu_get_info(), the ncpu_version field of the info argument must be set
  to NCPU_INFO_VERSION prior to the call.

RESTRICTIONS
  The information returned by these functions is a snapshot of the
  platform/partition configuration at the time the information is sampled.
  The data may be stale by the time the caller uses the information.

RETURN VALUES
  The cpu_get_info() function returns the following values:

  0   Success.

  -1  Failure. In this case, errno is set to indicate the error.

  The cpu_get_num() and cpu_get_max() functions return values as stated in
  the DESCRIPTION. These functions always complete successfully.

ERRORS
  The cpu_get_info() function fails,  it sets errno to one of the following
  values:

  [EFAULT]
      The info argument or one of the cpuset_t elements, points to an invalid
      address.

  [EINVAL]
      One or more of the cpuset_t elements of the info argument points to an
      invalid CPU set, possibly one that was not created by cpusetcreate().

  [EPERM]
      The version number specified in the ncpu_version field of the info
      argument is not recognized by the system.

SEE ALSO
  Functions: cpusetops(3), numa_intro(3)

Index for Section 3

Alphabetical listing for C

Top of page