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+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/sched_mc_power_savings
+ /sys/devices/system/cpu/sched_smt_power_savings
+Date: June 2006
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Discover and adjust the kernel's multi-core scheduler support.
+
+ Possible values are:
+
+ 0 - No power saving load balance (default value)
+ 1 - Fill one thread/core/package first for long running threads
+ 2 - Also bias task wakeups to semi-idle cpu package for power
+ savings
+
+ sched_mc_power_savings is dependent upon SCHED_MC, which is
+ itself architecture dependent.
+
+ sched_smt_power_savings is dependent upon SCHED_SMT, which
+ is itself architecture dependent.
+
+ The two files are independent of each other. It is possible
+ that one file may be present without the other.
+
+ Introduced by git commit 5c45bf27.
+
+
+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#/node
+Date: October 2009
+Contact: Linux memory management mailing list <linux-mm@kvack.org>
+Description: Discover NUMA node a CPU belongs to
+
+ When CONFIG_NUMA is enabled, a symbolic link that points
+ to the corresponding NUMA node directory.
+
+ For example, the following symlink is created for cpu42
+ in NUMA node 2:
+
+ /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
+
+
+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/cpuidle/current_driver
+ /sys/devices/system/cpu/cpuidle/current_governer_ro
+Date: September 2007
+Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
+Description: Discover cpuidle policy and mechanism
+
+ Various CPUs today support multiple idle levels that are
+ differentiated by varying exit latencies and power
+ consumption during idle.
+
+ Idle policy (governor) is differentiated from idle mechanism
+ (driver)
+
+ current_driver: displays current idle mechanism
+
+ current_governor_ro: displays current idle policy
+
+ See files in Documentation/cpuidle/ 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
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