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Commit | Line | Data |
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2ceb3fb0 AC |
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 | ||
e6dcfa7c AC |
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 | ||
2ceb3fb0 | 36 | |
d93fc863 AC |
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 | ||
663fb2fc AC |
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 | ||
2fad2d9b ML |
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 |