| Alex Chiang | 2ceb3fb | 2009-10-21 21:45:20 -0600 | [diff] [blame] | 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 | |
| 7 | Individual CPU attributes are contained in subdirectories |
| 8 | named by the kernel's logical CPU number, e.g.: |
| 9 | |
| 10 | /sys/devices/system/cpu/cpu#/ |
| 11 | |
| Alex Chiang | e6dcfa7 | 2009-10-21 21:45:36 -0600 | [diff] [blame^] | 12 | What: /sys/devices/system/cpu/sched_mc_power_savings |
| 13 | /sys/devices/system/cpu/sched_smt_power_savings |
| 14 | Date: June 2006 |
| 15 | Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| 16 | Description: Discover and adjust the kernel's multi-core scheduler support. |
| 17 | |
| 18 | Possible values are: |
| 19 | |
| 20 | 0 - No power saving load balance (default value) |
| 21 | 1 - Fill one thread/core/package first for long running threads |
| 22 | 2 - Also bias task wakeups to semi-idle cpu package for power |
| 23 | savings |
| 24 | |
| 25 | sched_mc_power_savings is dependent upon SCHED_MC, which is |
| 26 | itself architecture dependent. |
| 27 | |
| 28 | sched_smt_power_savings is dependent upon SCHED_SMT, which |
| 29 | is itself architecture dependent. |
| 30 | |
| 31 | The two files are independent of each other. It is possible |
| 32 | that one file may be present without the other. |
| 33 | |
| 34 | Introduced by git commit 5c45bf27. |
| 35 | |
| Alex Chiang | 2ceb3fb | 2009-10-21 21:45:20 -0600 | [diff] [blame] | 36 | |
| Alex Chiang | d93fc86 | 2009-10-21 21:45:25 -0600 | [diff] [blame] | 37 | What: /sys/devices/system/cpu/kernel_max |
| 38 | /sys/devices/system/cpu/offline |
| 39 | /sys/devices/system/cpu/online |
| 40 | /sys/devices/system/cpu/possible |
| 41 | /sys/devices/system/cpu/present |
| 42 | Date: December 2008 |
| 43 | Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| 44 | Description: CPU topology files that describe kernel limits related to |
| 45 | hotplug. Briefly: |
| 46 | |
| 47 | kernel_max: the maximum cpu index allowed by the kernel |
| 48 | configuration. |
| 49 | |
| 50 | offline: cpus that are not online because they have been |
| 51 | HOTPLUGGED off or exceed the limit of cpus allowed by the |
| 52 | kernel configuration (kernel_max above). |
| 53 | |
| 54 | online: cpus that are online and being scheduled. |
| 55 | |
| 56 | possible: cpus that have been allocated resources and can be |
| 57 | brought online if they are present. |
| 58 | |
| 59 | present: cpus that have been identified as being present in |
| 60 | the system. |
| 61 | |
| 62 | See Documentation/cputopology.txt for more information. |
| 63 | |
| 64 | |
| Alex Chiang | 663fb2f | 2009-10-21 21:45:31 -0600 | [diff] [blame] | 65 | What: /sys/devices/system/cpu/cpu#/topology/core_id |
| 66 | /sys/devices/system/cpu/cpu#/topology/core_siblings |
| 67 | /sys/devices/system/cpu/cpu#/topology/core_siblings_list |
| 68 | /sys/devices/system/cpu/cpu#/topology/physical_package_id |
| 69 | /sys/devices/system/cpu/cpu#/topology/thread_siblings |
| 70 | /sys/devices/system/cpu/cpu#/topology/thread_siblings_list |
| 71 | Date: December 2008 |
| 72 | Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> |
| 73 | Description: CPU topology files that describe a logical CPU's relationship |
| 74 | to other cores and threads in the same physical package. |
| 75 | |
| 76 | One cpu# directory is created per logical CPU in the system, |
| 77 | e.g. /sys/devices/system/cpu/cpu42/. |
| 78 | |
| 79 | Briefly, the files above are: |
| 80 | |
| 81 | core_id: the CPU core ID of cpu#. Typically it is the |
| 82 | hardware platform's identifier (rather than the kernel's). |
| 83 | The actual value is architecture and platform dependent. |
| 84 | |
| 85 | core_siblings: internal kernel map of cpu#'s hardware threads |
| 86 | within the same physical_package_id. |
| 87 | |
| 88 | core_siblings_list: human-readable list of the logical CPU |
| 89 | numbers within the same physical_package_id as cpu#. |
| 90 | |
| 91 | physical_package_id: physical package id of cpu#. Typically |
| 92 | corresponds to a physical socket number, but the actual value |
| 93 | is architecture and platform dependent. |
| 94 | |
| 95 | thread_siblings: internel kernel map of cpu#'s hardware |
| 96 | threads within the same core as cpu# |
| 97 | |
| 98 | thread_siblings_list: human-readable list of cpu#'s hardware |
| 99 | threads within the same core as cpu# |
| 100 | |
| 101 | See Documentation/cputopology.txt for more information. |
| 102 | |
| 103 | |
| Mark Langsdorf | 2fad2d9 | 2009-04-09 15:31:53 +0200 | [diff] [blame] | 104 | What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X |
| 105 | Date: August 2008 |
| 106 | KernelVersion: 2.6.27 |
| 107 | Contact: mark.langsdorf@amd.com |
| 108 | Description: These files exist in every cpu's cache index directories. |
| 109 | There are currently 2 cache_disable_# files in each |
| 110 | directory. Reading from these files on a supported |
| 111 | processor will return that cache disable index value |
| 112 | for that processor and node. Writing to one of these |
| 113 | files will cause the specificed cache index to be disabled. |
| 114 | |
| 115 | Currently, only AMD Family 10h Processors support cache index |
| 116 | disable, and only for their L3 caches. See the BIOS and |
| 117 | Kernel Developer's Guide at |
| 118 | http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf |
| 119 | for formatting information and other details on the |
| 120 | cache index disable. |
| 121 | Users: joachim.deguara@amd.com |