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Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-system-cpu')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu new file mode 100644 index 000000000000..a703b9e9aeb9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -0,0 +1,156 @@ +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 |