| What: /sys/devices/system/cpu/ |
| Date: pre-git history |
| Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| Description: |
| A collection of both global and individual CPU attributes |
| |
| Individual CPU attributes are contained in subdirectories |
| named by the kernel's logical CPU number, e.g.: |
| |
| /sys/devices/system/cpu/cpu#/ |
| |
| |
| What: /sys/devices/system/cpu/kernel_max |
| /sys/devices/system/cpu/offline |
| /sys/devices/system/cpu/online |
| /sys/devices/system/cpu/possible |
| /sys/devices/system/cpu/present |
| Date: December 2008 |
| Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| Description: CPU topology files that describe kernel limits related to |
| hotplug. Briefly: |
| |
| kernel_max: the maximum cpu index allowed by the kernel |
| configuration. |
| |
| offline: cpus that are not online because they have been |
| HOTPLUGGED off or exceed the limit of cpus allowed by the |
| kernel configuration (kernel_max above). |
| |
| online: cpus that are online and being scheduled. |
| |
| possible: cpus that have been allocated resources and can be |
| brought online if they are present. |
| |
| present: cpus that have been identified as being present in |
| the system. |
| |
| See Documentation/cputopology.txt for more information. |
| |
| |
| What: /sys/devices/system/cpu/cpu#/topology/core_id |
| /sys/devices/system/cpu/cpu#/topology/core_siblings |
| /sys/devices/system/cpu/cpu#/topology/core_siblings_list |
| /sys/devices/system/cpu/cpu#/topology/physical_package_id |
| /sys/devices/system/cpu/cpu#/topology/thread_siblings |
| /sys/devices/system/cpu/cpu#/topology/thread_siblings_list |
| Date: December 2008 |
| Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| Description: CPU topology files that describe a logical CPU's relationship |
| to other cores and threads in the same physical package. |
| |
| One cpu# directory is created per logical CPU in the system, |
| e.g. /sys/devices/system/cpu/cpu42/. |
| |
| Briefly, the files above are: |
| |
| core_id: the CPU core ID of cpu#. Typically it is the |
| hardware platform's identifier (rather than the kernel's). |
| The actual value is architecture and platform dependent. |
| |
| core_siblings: internal kernel map of cpu#'s hardware threads |
| within the same physical_package_id. |
| |
| core_siblings_list: human-readable list of the logical CPU |
| numbers within the same physical_package_id as cpu#. |
| |
| physical_package_id: physical package id of cpu#. Typically |
| corresponds to a physical socket number, but the actual value |
| is architecture and platform dependent. |
| |
| thread_siblings: internel kernel map of cpu#'s hardware |
| threads within the same core as cpu# |
| |
| thread_siblings_list: human-readable list of cpu#'s hardware |
| threads within the same core as cpu# |
| |
| See Documentation/cputopology.txt for more information. |
| |
| |
| What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X |
| Date: August 2008 |
| KernelVersion: 2.6.27 |
| Contact: mark.langsdorf@amd.com |
| Description: These files exist in every cpu's cache index directories. |
| There are currently 2 cache_disable_# files in each |
| directory. Reading from these files on a supported |
| processor will return that cache disable index value |
| for that processor and node. Writing to one of these |
| files will cause the specificed cache index to be disabled. |
| |
| Currently, only AMD Family 10h Processors support cache index |
| disable, and only for their L3 caches. See the BIOS and |
| Kernel Developer's Guide at |
| http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf |
| for formatting information and other details on the |
| cache index disable. |
| Users: joachim.deguara@amd.com |