Documentation/ABI/testing/sysfs-devices-system-cpu

   1 What:           /sys/devices/system/cpu/
   2 Date:           pre-git history
   3 Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
   4 Description:
   5                 A collection of both global and individual CPU attributes
   6
   7                 Individual CPU attributes are contained in subdirectories
   8                 named by the kernel's logical CPU number, e.g.:
   9
  10                 /sys/devices/system/cpu/cpu#/
  11
  12
  13 What:           /sys/devices/system/cpu/kernel_max
  14                 /sys/devices/system/cpu/offline
  15                 /sys/devices/system/cpu/online
  16                 /sys/devices/system/cpu/possible
  17                 /sys/devices/system/cpu/present
  18 Date:           December 2008
  19 Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
  20 Description:    CPU topology files that describe kernel limits related to
  21                 hotplug. Briefly:
  22
  23                 kernel_max: the maximum cpu index allowed by the kernel
  24                 configuration.
  25
  26                 offline: cpus that are not online because they have been
  27                 HOTPLUGGED off or exceed the limit of cpus allowed by the
  28                 kernel configuration (kernel_max above).
  29
  30                 online: cpus that are online and being scheduled.
  31
  32                 possible: cpus that have been allocated resources and can be
  33                 brought online if they are present.
  34
  35                 present: cpus that have been identified as being present in
  36                 the system.
  37
  38                 See Documentation/cputopology.txt for more information.
  39
  40
  41 What:           /sys/devices/system/cpu/cpu#/topology/core_id
  42                 /sys/devices/system/cpu/cpu#/topology/core_siblings
  43                 /sys/devices/system/cpu/cpu#/topology/core_siblings_list
  44                 /sys/devices/system/cpu/cpu#/topology/physical_package_id
  45                 /sys/devices/system/cpu/cpu#/topology/thread_siblings
  46                 /sys/devices/system/cpu/cpu#/topology/thread_siblings_list
  47 Date:           December 2008
  48 Contact:        Linux kernel mailing list <linux-kernel@vger.kernel.org>
  49 Description:    CPU topology files that describe a logical CPU's relationship
  50                 to other cores and threads in the same physical package.
  51
  52                 One cpu# directory is created per logical CPU in the system,
  53                 e.g. /sys/devices/system/cpu/cpu42/.
  54
  55                 Briefly, the files above are:
  56
  57                 core_id: the CPU core ID of cpu#. Typically it is the
  58                 hardware platform's identifier (rather than the kernel's).
  59                 The actual value is architecture and platform dependent.
  60
  61                 core_siblings: internal kernel map of cpu#'s hardware threads
  62                 within the same physical_package_id.
  63
  64                 core_siblings_list: human-readable list of the logical CPU
  65                 numbers within the same physical_package_id as cpu#.
  66
  67                 physical_package_id: physical package id of cpu#. Typically
  68                 corresponds to a physical socket number, but the actual value
  69                 is architecture and platform dependent.
  70
  71                 thread_siblings: internel kernel map of cpu#'s hardware
  72                 threads within the same core as cpu#
  73
  74                 thread_siblings_list: human-readable list of cpu#'s hardware
  75                 threads within the same core as cpu#
  76
  77                 See Documentation/cputopology.txt for more information.
  78
  79
  80 What:      /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X
  81 Date:      August 2008
  82 KernelVersion:  2.6.27
  83 Contact:        mark.langsdorf@amd.com
  84 Description:    These files exist in every cpu's cache index directories.
  85                 There are currently 2 cache_disable_# files in each
  86                 directory.  Reading from these files on a supported
  87                 processor will return that cache disable index value
  88                 for that processor and node.  Writing to one of these
  89                 files will cause the specificed cache index to be disabled.
  90
  91                 Currently, only AMD Family 10h Processors support cache index
  92                 disable, and only for their L3 caches.  See the BIOS and
  93                 Kernel Developer's Guide at
  94                 http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf
  95                 for formatting information and other details on the
  96                 cache index disable.
  97 Users:    joachim.deguara@amd.com