What: /sys/devices/system/cpu/ Date: pre-git history Contact: Linux kernel mailing list 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 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 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