sysfs-devices-system-cpu 3.5 KB

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