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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-12-04 09:59:47 -0500 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-12-04 09:59:47 -0500 |
| commit | 5cb2faa6ede7ada9cb2bffc832c4ce60f53d6834 (patch) | |
| tree | 7b72b66081d042a41dc822575503133364857ce2 /Documentation/ABI/testing/sysfs-devices-system-cpu | |
| parent | e0ee98513d1a2e24d2ddbdecf4216bcca29d1158 (diff) | |
| parent | 6060e8df517847bf445ebc61de7d4d9c7faae990 (diff) | |
Merge branch 'pending-misc' (early part) into devel
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 @@ | |||
| 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 | |||
| 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 | |||
| 36 | |||
| 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 | |||
| 65 | |||
| 66 | What: /sys/devices/system/cpu/cpu#/node | ||
| 67 | Date: October 2009 | ||
| 68 | Contact: Linux memory management mailing list <linux-mm@kvack.org> | ||
| 69 | Description: Discover NUMA node a CPU belongs to | ||
| 70 | |||
| 71 | When CONFIG_NUMA is enabled, a symbolic link that points | ||
| 72 | to the corresponding NUMA node directory. | ||
| 73 | |||
| 74 | For example, the following symlink is created for cpu42 | ||
| 75 | in NUMA node 2: | ||
| 76 | |||
| 77 | /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2 | ||
| 78 | |||
| 79 | |||
| 80 | What: /sys/devices/system/cpu/cpu#/topology/core_id | ||
| 81 | /sys/devices/system/cpu/cpu#/topology/core_siblings | ||
| 82 | /sys/devices/system/cpu/cpu#/topology/core_siblings_list | ||
| 83 | /sys/devices/system/cpu/cpu#/topology/physical_package_id | ||
| 84 | /sys/devices/system/cpu/cpu#/topology/thread_siblings | ||
| 85 | /sys/devices/system/cpu/cpu#/topology/thread_siblings_list | ||
| 86 | Date: December 2008 | ||
| 87 | Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> | ||
| 88 | Description: CPU topology files that describe a logical CPU's relationship | ||
| 89 | to other cores and threads in the same physical package. | ||
| 90 | |||
| 91 | One cpu# directory is created per logical CPU in the system, | ||
| 92 | e.g. /sys/devices/system/cpu/cpu42/. | ||
| 93 | |||
| 94 | Briefly, the files above are: | ||
| 95 | |||
| 96 | core_id: the CPU core ID of cpu#. Typically it is the | ||
| 97 | hardware platform's identifier (rather than the kernel's). | ||
| 98 | The actual value is architecture and platform dependent. | ||
| 99 | |||
| 100 | core_siblings: internal kernel map of cpu#'s hardware threads | ||
| 101 | within the same physical_package_id. | ||
| 102 | |||
| 103 | core_siblings_list: human-readable list of the logical CPU | ||
| 104 | numbers within the same physical_package_id as cpu#. | ||
| 105 | |||
| 106 | physical_package_id: physical package id of cpu#. Typically | ||
| 107 | corresponds to a physical socket number, but the actual value | ||
| 108 | is architecture and platform dependent. | ||
| 109 | |||
| 110 | thread_siblings: internel kernel map of cpu#'s hardware | ||
| 111 | threads within the same core as cpu# | ||
| 112 | |||
| 113 | thread_siblings_list: human-readable list of cpu#'s hardware | ||
| 114 | threads within the same core as cpu# | ||
| 115 | |||
| 116 | See Documentation/cputopology.txt for more information. | ||
| 117 | |||
| 118 | |||
| 119 | What: /sys/devices/system/cpu/cpuidle/current_driver | ||
| 120 | /sys/devices/system/cpu/cpuidle/current_governer_ro | ||
| 121 | Date: September 2007 | ||
| 122 | Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> | ||
| 123 | Description: Discover cpuidle policy and mechanism | ||
| 124 | |||
| 125 | Various CPUs today support multiple idle levels that are | ||
| 126 | differentiated by varying exit latencies and power | ||
| 127 | consumption during idle. | ||
| 128 | |||
| 129 | Idle policy (governor) is differentiated from idle mechanism | ||
| 130 | (driver) | ||
| 131 | |||
| 132 | current_driver: displays current idle mechanism | ||
| 133 | |||
| 134 | current_governor_ro: displays current idle policy | ||
| 135 | |||
| 136 | See files in Documentation/cpuidle/ for more information. | ||
| 137 | |||
| 138 | |||
| 139 | What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X | ||
| 140 | Date: August 2008 | ||
| 141 | KernelVersion: 2.6.27 | ||
| 142 | Contact: mark.langsdorf@amd.com | ||
| 143 | Description: These files exist in every cpu's cache index directories. | ||
| 144 | There are currently 2 cache_disable_# files in each | ||
| 145 | directory. Reading from these files on a supported | ||
| 146 | processor will return that cache disable index value | ||
| 147 | for that processor and node. Writing to one of these | ||
| 148 | files will cause the specificed cache index to be disabled. | ||
| 149 | |||
| 150 | Currently, only AMD Family 10h Processors support cache index | ||
| 151 | disable, and only for their L3 caches. See the BIOS and | ||
| 152 | Kernel Developer's Guide at | ||
| 153 | http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/31116-Public-GH-BKDG_3.20_2-4-09.pdf | ||
| 154 | for formatting information and other details on the | ||
| 155 | cache index disable. | ||
| 156 | Users: joachim.deguara@amd.com | ||
