1 What: /sys/devices/system/cpu/ 1 What: /sys/devices/system/cpu/
2 Date: pre-git history 2 Date: pre-git history
3 Contact: Linux kernel mailing list <linu 3 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
4 Description: 4 Description:
5 A collection of both global an 5 A collection of both global and individual CPU attributes
6 6
7 Individual CPU attributes are 7 Individual CPU attributes are contained in subdirectories
8 named by the kernel's logical 8 named by the kernel's logical CPU number, e.g.:
9 9
10 /sys/devices/system/cpu/cpuX/ !! 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
11 36
12 What: /sys/devices/system/cpu/kernel 37 What: /sys/devices/system/cpu/kernel_max
13 /sys/devices/system/cpu/offlin 38 /sys/devices/system/cpu/offline
14 /sys/devices/system/cpu/online 39 /sys/devices/system/cpu/online
15 /sys/devices/system/cpu/possib 40 /sys/devices/system/cpu/possible
16 /sys/devices/system/cpu/presen 41 /sys/devices/system/cpu/present
17 Date: December 2008 42 Date: December 2008
18 Contact: Linux kernel mailing list <linu 43 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
19 Description: CPU topology files that descri 44 Description: CPU topology files that describe kernel limits related to
20 hotplug. Briefly: 45 hotplug. Briefly:
21 46
22 kernel_max: the maximum cpu in 47 kernel_max: the maximum cpu index allowed by the kernel
23 configuration. 48 configuration.
24 49
25 offline: cpus that are not onl 50 offline: cpus that are not online because they have been
26 HOTPLUGGED off or exceed the l 51 HOTPLUGGED off or exceed the limit of cpus allowed by the
27 kernel configuration (kernel_m 52 kernel configuration (kernel_max above).
28 53
29 online: cpus that are online a 54 online: cpus that are online and being scheduled.
30 55
31 possible: cpus that have been 56 possible: cpus that have been allocated resources and can be
32 brought online if they are pre 57 brought online if they are present.
33 58
34 present: cpus that have been i 59 present: cpus that have been identified as being present in
35 the system. 60 the system.
36 61
37 See Documentation/admin-guide/ !! 62 See Documentation/cputopology.txt for more information.
38 63
39 64
40 What: /sys/devices/system/cpu/probe <<
41 /sys/devices/system/cpu/releas <<
42 Date: November 2009 <<
43 Contact: Linux kernel mailing list <linu <<
44 Description: Dynamic addition and removal o <<
45 removal, this is meant complet <<
46 from the system. <<
47 <<
48 probe: writes to this file wil <<
49 system. Information written t <<
50 architecture specific. <<
51 <<
52 release: writes to this file d <<
53 the system. Information writt <<
54 is architecture specific. <<
55 65
56 What: /sys/devices/system/cpu/cpuX/n !! 66 What: /sys/devices/system/cpu/cpu#/node
57 Date: October 2009 67 Date: October 2009
58 Contact: Linux memory management mailin< 68 Contact: Linux memory management mailing list <linux-mm@kvack.org>
59 Description: Discover NUMA node a CPU belon 69 Description: Discover NUMA node a CPU belongs to
60 70
61 When CONFIG_NUMA is enabled, a 71 When CONFIG_NUMA is enabled, a symbolic link that points
62 to the corresponding NUMA node 72 to the corresponding NUMA node directory.
63 73
64 For example, the following sym 74 For example, the following symlink is created for cpu42
65 in NUMA node 2: 75 in NUMA node 2:
66 76
67 /sys/devices/system/cpu/cpu42/ 77 /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
68 78
69 79
70 What: /sys/devices/system/cpu/cpuX/t !! 80 What: /sys/devices/system/cpu/cpu#/topology/core_id
71 /sys/devices/system/cpu/cpuX/t !! 81 /sys/devices/system/cpu/cpu#/topology/core_siblings
72 /sys/devices/system/cpu/cpuX/t !! 82 /sys/devices/system/cpu/cpu#/topology/core_siblings_list
73 /sys/devices/system/cpu/cpuX/t !! 83 /sys/devices/system/cpu/cpu#/topology/physical_package_id
74 /sys/devices/system/cpu/cpuX/t !! 84 /sys/devices/system/cpu/cpu#/topology/thread_siblings
75 /sys/devices/system/cpu/cpuX/t !! 85 /sys/devices/system/cpu/cpu#/topology/thread_siblings_list
76 Date: December 2008 86 Date: December 2008
77 Contact: Linux kernel mailing list <linu 87 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
78 Description: CPU topology files that descri 88 Description: CPU topology files that describe a logical CPU's relationship
79 to other cores and threads in 89 to other cores and threads in the same physical package.
80 90
81 One cpuX directory is created !! 91 One cpu# directory is created per logical CPU in the system,
82 e.g. /sys/devices/system/cpu/c 92 e.g. /sys/devices/system/cpu/cpu42/.
83 93
84 Briefly, the files above are: 94 Briefly, the files above are:
85 95
86 core_siblings: internal kernel !! 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
87 within the same physical_packa 101 within the same physical_package_id.
88 102
89 core_siblings_list: human-read 103 core_siblings_list: human-readable list of the logical CPU
90 numbers within the same physic !! 104 numbers within the same physical_package_id as cpu#.
91 105
92 physical_package_id: physical !! 106 physical_package_id: physical package id of cpu#. Typically
93 corresponds to a physical sock 107 corresponds to a physical socket number, but the actual value
94 is architecture and platform d 108 is architecture and platform dependent.
95 109
96 thread_siblings: internal kern !! 110 thread_siblings: internel kernel map of cpu#'s hardware
97 threads within the same core a !! 111 threads within the same core as cpu#
98 112
99 thread_siblings_list: human-re !! 113 thread_siblings_list: human-readable list of cpu#'s hardware
100 threads within the same core a !! 114 threads within the same core as cpu#
101 115
102 ppin: human-readable Protected !! 116 See Documentation/cputopology.txt for more information.
103 Number of the socket the cpu# <<
104 one per physical_package_id. F <<
105 admin. <<
106 117
107 See Documentation/admin-guide/ <<
108 118
109 !! 119 What: /sys/devices/system/cpu/cpuidle/current_driver
110 What: /sys/devices/system/cpu/cpuidl <<
111 /sys/devices/system/cpu/cpuidl <<
112 /sys/devices/system/cpu/cpuidl <<
113 /sys/devices/system/cpu/cpuidl 120 /sys/devices/system/cpu/cpuidle/current_governer_ro
114 Date: September 2007 121 Date: September 2007
115 Contact: Linux kernel mailing list <linu 122 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
116 Description: Discover cpuidle policy and me 123 Description: Discover cpuidle policy and mechanism
117 124
118 Various CPUs today support mul 125 Various CPUs today support multiple idle levels that are
119 differentiated by varying exit 126 differentiated by varying exit latencies and power
120 consumption during idle. 127 consumption during idle.
121 128
122 Idle policy (governor) is diff 129 Idle policy (governor) is differentiated from idle mechanism
123 (driver). !! 130 (driver)
124 <<
125 available_governors: (RO) disp <<
126 available governors. <<
127 <<
128 current_driver: (RO) displays <<
129 <<
130 current_governor: (RW) display <<
131 switch the governor at runtime <<
132 <<
133 current_governor_ro: (RO) disp <<
134 131
135 See Documentation/admin-guide/ !! 132 current_driver: displays current idle mechanism
136 Documentation/driver-api/pm/cp <<
137 133
>> 134 current_governor_ro: displays current idle policy
138 135
139 What: /sys/devices/system/cpu/cpuX/c !! 136 See files in Documentation/cpuidle/ for more information.
140 /sys/devices/system/cpu/cpuX/c <<
141 /sys/devices/system/cpu/cpuX/c <<
142 /sys/devices/system/cpu/cpuX/c <<
143 /sys/devices/system/cpu/cpuX/c <<
144 /sys/devices/system/cpu/cpuX/c <<
145 /sys/devices/system/cpu/cpuX/c <<
146 Date: September 2007 <<
147 KernelVersion: v2.6.24 <<
148 Contact: Linux power management list <li <<
149 Description: <<
150 The directory /sys/devices/sys <<
151 logical CPU specific cpuidle i <<
152 The processor idle states whic <<
153 following attributes: <<
154 <<
155 ======== ==== ================ <<
156 name: (RO) Name of the idle <<
157 <<
158 latency: (RO) The latency to e <<
159 microseconds). <<
160 <<
161 power: (RO) The power consum <<
162 milliwatts). <<
163 <<
164 time: (RO) The total time s <<
165 (in microseconds <<
166 <<
167 usage: (RO) Number of times <<
168 <<
169 above: (RO) Number of times <<
170 observed CPU idl <<
171 (a count). <<
172 <<
173 below: (RO) Number of times <<
174 observed CPU idl <<
175 (a count). <<
176 ======== ==== ================ <<
177 <<
178 What: /sys/devices/system/cpu/cpuX/c <<
179 Date: February 2008 <<
180 KernelVersion: v2.6.25 <<
181 Contact: Linux power management list <li <<
182 Description: <<
183 (RO) A small description about <<
184 <<
185 <<
186 What: /sys/devices/system/cpu/cpuX/c <<
187 Date: March 2012 <<
188 KernelVersion: v3.10 <<
189 Contact: Linux power management list <li <<
190 Description: <<
191 (RW) Option to disable this id <<
192 the effect of the disable vari <<
193 of a particular governor. In t <<
194 it is not coherent, i.e. if on <<
195 all deeper states are disabled <<
196 does not reflect it. Likewise, <<
197 lighter state still is disable <<
198 <<
199 What: /sys/devices/system/cpu/cpuX/c <<
200 Date: December 2019 <<
201 KernelVersion: v5.6 <<
202 Contact: Linux power management list <li <<
203 Description: <<
204 (RO) The default status of thi <<
205 <<
206 What: /sys/devices/system/cpu/cpuX/c <<
207 Date: March 2014 <<
208 KernelVersion: v3.15 <<
209 Contact: Linux power management list <li <<
210 Description: <<
211 (RO) Display the target reside <<
212 time (in microseconds) this cp <<
213 to make the transition worth t <<
214 <<
215 What: /sys/devices/system/cpu/cpuX/c <<
216 Date: March 2018 <<
217 KernelVersion: v4.17 <<
218 Contact: Linux power management list <li <<
219 Description: <<
220 Idle state usage statistics re <<
221 <<
222 This attribute group is only p <<
223 used in suspend-to-idle with s <<
224 <<
225 What: /sys/devices/system/cpu/cpuX/c <<
226 Date: March 2018 <<
227 KernelVersion: v4.17 <<
228 Contact: Linux power management list <li <<
229 Description: <<
230 Total time spent by the CPU in <<
231 tick suspended) after requesti <<
232 <<
233 What: /sys/devices/system/cpu/cpuX/c <<
234 Date: March 2018 <<
235 KernelVersion: v4.17 <<
236 Contact: Linux power management list <li <<
237 Description: <<
238 Total number of times this sta <<
239 while entering suspend-to-idle <<
240 <<
241 What: /sys/devices/system/cpu/cpuX/c <<
242 Date: pre-git history <<
243 Contact: linux-pm@vger.kernel.org <<
244 Description: Discover and change clock spee <<
245 <<
246 Clock scaling allows you to ch <<
247 CPUs on the fly. This is a nic <<
248 power, because the lower the c <<
249 the CPU consumes. <<
250 <<
251 There are many knobs to tweak <<
252 <<
253 See files in Documentation/cpu <<
254 <<
255 <<
256 What: /sys/devices/system/cpu/cpuX/c <<
257 Date: June 2013 <<
258 Contact: linux-pm@vger.kernel.org <<
259 Description: Discover CPUs in the same CPU <<
260 <<
261 freqdomain_cpus is the list of <<
262 the same clock/freq domain (po <<
263 That information may be hidden <<
264 value of related_cpus may be d <<
265 attribute is useful for user s <<
266 power/performance results for <<
267 <<
268 This file is only present if t <<
269 drivers are in use. <<
270 137
271 138
272 What: /sys/devices/system/cpu/cpu*/c !! 139 What: /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X
273 Date: August 2008 !! 140 Date: August 2008
274 KernelVersion: 2.6.27 141 KernelVersion: 2.6.27
275 Contact: Linux kernel mailing list <linu !! 142 Contact: mark.langsdorf@amd.com
276 Description: Disable L3 cache indices !! 143 Description: These files exist in every cpu's cache index directories.
277 !! 144 There are currently 2 cache_disable_# files in each
278 These files exist in every CPU !! 145 directory. Reading from these files on a supported
279 cache_disable_{0,1} file corre !! 146 processor will return that cache disable index value
280 can be used to disable a cache !! 147 for that processor and node. Writing to one of these
281 on a processor with this funct !! 148 files will cause the specificed cache index to be disabled.
282 disabled index for that node. !! 149
283 node, or per internal node on !! 150 Currently, only AMD Family 10h Processors support cache index
284 index to one of these files wi !! 151 disable, and only for their L3 caches. See the BIOS and
285 index to be disabled. !! 152 Kernel Developer's Guide at
286 !! 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
287 All AMD processors with L3 cac !! 154 for formatting information and other details on the
288 For details, see BKDGs at !! 155 cache index disable.
289 https://www.amd.com/en/support !! 156 Users: joachim.deguara@amd.com
290 <<
291 <<
292 What: /sys/devices/system/cpu/cpufre <<
293 Date: August 2012 <<
294 Contact: Linux kernel mailing list <linu <<
295 Description: Processor frequency boosting c <<
296 <<
297 This switch controls the boost <<
298 Boosting allows the CPU and th <<
299 beyond its nominal limit. <<
300 <<
301 More details can be found in <<
302 Documentation/admin-guide/pm/c <<
303 <<
304 <<
305 What: /sys/devices/system/cpu/cpuX/c <<
306 /sys/devices/system/cpu/cpuX/c <<
307 Date: April 2013 <<
308 Contact: kexec@lists.infradead.org <<
309 Description: address and size of the percpu <<
310 <<
311 crash_notes: the physical addr <<
312 note of cpuX. <<
313 <<
314 crash_notes_size: size of the <<
315 <<
316 <<
317 What: /sys/devices/system/cpu/intel_ <<
318 /sys/devices/system/cpu/intel_ <<
319 /sys/devices/system/cpu/intel_ <<
320 Date: February 2013 <<
321 Contact: linux-pm@vger.kernel.org <<
322 Description: Parameters for the Intel P-sta <<
323 <<
324 Logic for selecting the curren <<
325 Sandybridge+ processors. The t <<
326 limits for the P-state that wi <<
327 driver. <<
328 <<
329 max_perf_pct: limits the maxim <<
330 the driver stated as a percent <<
331 <<
332 min_perf_pct: limits the minim <<
333 the driver stated as a percent <<
334 <<
335 no_turbo: limits the driver to <<
336 frequency range. <<
337 <<
338 More details can be found in <<
339 Documentation/admin-guide/pm/i <<
340 <<
341 What: /sys/devices/system/cpu/cpu*/c <<
342 Date: July 2014(documented, existed <<
343 Contact: Sudeep Holla <sudeep.holla@arm. <<
344 Linux kernel mailing list <linu <<
345 Description: Parameters for the CPU cache a <<
346 <<
347 allocation_policy: <<
348 - WriteAllocate: <<
349 alloca <<
350 on a c <<
351 - ReadAllocate: <<
352 alloca <<
353 on a c <<
354 - ReadWriteAllocate: <<
355 both w <<
356 <<
357 coherency_line_size: <<
358 the minim <<
359 transferr <<
360 <<
361 level: <<
362 the cache hierarchy in <<
363 <<
364 number_of_sets: <<
365 total number o <<
366 collection of <<
367 <<
368 physical_line_partition: <<
369 number of phys <<
370 <<
371 shared_cpu_list: <<
372 the list of lo <<
373 <<
374 shared_cpu_map: <<
375 logical cpu ma <<
376 the cache <<
377 <<
378 size: <<
379 the total cache size i <<
380 <<
381 type: <<
382 - Instruction: cache t <<
383 - Data: cache that onl <<
384 - Unified: cache that <<
385 <<
386 ways_of_associativity: <<
387 degree of freedom in p <<
388 of memory in the cache <<
389 <<
390 write_policy: <<
391 - WriteThrough: <<
392 data i <<
393 and to <<
394 - WriteBack: <<
395 data is w <<
396 the modif <<
397 memory on <<
398 <<
399 <<
400 What: /sys/devices/system/cpu/cpu*/c <<
401 Date: September 2016 <<
402 Contact: Linux kernel mailing list <linu <<
403 Description: Cache id <<
404 <<
405 The id provides a unique numbe <<
406 a cache of a particular type. <<
407 3 unified cache on each socket <<
408 assign them ids 0, 1, 2, ... <<
409 <<
410 Note that id value can be non- <<
411 caches typically exist per cor <<
412 power of two cores on a socket <<
413 numbered 0, 1, 2, 3, 4, 5, 8, <<
414 <<
415 What: /sys/devices/system/cpu/cpuX/c <<
416 /sys/devices/system/cpu/cpuX/c <<
417 /sys/devices/system/cpu/cpuX/c <<
418 /sys/devices/system/cpu/cpuX/c <<
419 /sys/devices/system/cpu/cpuX/c <<
420 /sys/devices/system/cpu/cpuX/c <<
421 /sys/devices/system/cpu/cpuX/c <<
422 /sys/devices/system/cpu/cpuX/c <<
423 /sys/devices/system/cpu/cpuX/c <<
424 Date: March 2016 <<
425 Contact: Linux kernel mailing list <linu <<
426 Linux for PowerPC mailing list< <<
427 Description: POWERNV CPUFreq driver's frequ <<
428 attributes <<
429 <<
430 'cpuX/cpufreq/throttle_stats' <<
431 throttle stat attributes for t <<
432 is common across all the cpus <<
433 throttle attributes exported i <<
434 <<
435 - turbo_stat : This file gives <<
436 frequency is throttled to lo <<
437 nominal frequency) range of <<
438 <<
439 - sub_turbo_stat : This file g <<
440 max frequency is throttled t <<
441 nominal frequency) range of <<
442 <<
443 - unthrottle : This file gives <<
444 frequency is unthrottled aft <<
445 <<
446 - powercap : This file gives t <<
447 frequency is throttled due t <<
448 <<
449 - overtemp : This file gives t <<
450 frequency is throttled due t <<
451 <<
452 - supply_fault : This file giv <<
453 max frequency is throttled d <<
454 <<
455 - overcurrent : This file give <<
456 max frequency is throttled d <<
457 <<
458 - occ_reset : This file gives <<
459 frequency is throttled due t <<
460 <<
461 The sysfs attributes represent <<
462 powercap, overtemp, supply_fau <<
463 the reasons provided by OCC fi <<
464 <<
465 What: /sys/devices/system/cpu/cpufre <<
466 /sys/devices/system/cpu/cpufre <<
467 /sys/devices/system/cpu/cpufre <<
468 /sys/devices/system/cpu/cpufre <<
469 /sys/devices/system/cpu/cpufre <<
470 /sys/devices/system/cpu/cpufre <<
471 /sys/devices/system/cpu/cpufre <<
472 /sys/devices/system/cpu/cpufre <<
473 /sys/devices/system/cpu/cpufre <<
474 Date: March 2016 <<
475 Contact: Linux kernel mailing list <linu <<
476 Linux for PowerPC mailing list< <<
477 Description: POWERNV CPUFreq driver's frequ <<
478 attributes <<
479 <<
480 'policyX/throttle_stats' direc <<
481 the /sys/devices/system/cpu/cp <<
482 attributes which give the freq <<
483 <<
484 What: /sys/devices/system/cpu/cpuX/r <<
485 /sys/devices/system/cpu/cpuX/r <<
486 /sys/devices/system/cpu/cpuX/r <<
487 /sys/devices/system/cpu/cpuX/r <<
488 /sys/devices/system/cpu/cpuX/r <<
489 Date: June 2016 <<
490 Contact: Linux ARM Kernel Mailing list < <<
491 Description: AArch64 CPU registers <<
492 <<
493 'identification' directory exp <<
494 identifying model and revision <<
495 <<
496 What: /sys/devices/system/cpu/aarch3 <<
497 Date: May 2021 <<
498 Contact: Linux ARM Kernel Mailing list < <<
499 Description: Identifies the subset of CPUs <<
500 AArch32 (32-bit ARM) applicati <<
501 /sys/devices/system/cpu/{offli <<
502 If absent, then all or none of <<
503 applications and execve() will <<
504 <<
505 What: /sys/devices/system/cpu/cpuX/c <<
506 Date: December 2016 <<
507 Contact: Linux kernel mailing list <linu <<
508 Description: information about CPUs heterog <<
509 <<
510 cpu_capacity: capacity of cpuX <<
511 <<
512 What: /sys/devices/system/cpu/vulner <<
513 /sys/devices/system/cpu/vulner <<
514 /sys/devices/system/cpu/vulner <<
515 /sys/devices/system/cpu/vulner <<
516 /sys/devices/system/cpu/vulner <<
517 /sys/devices/system/cpu/vulner <<
518 /sys/devices/system/cpu/vulner <<
519 /sys/devices/system/cpu/vulner <<
520 /sys/devices/system/cpu/vulner <<
521 /sys/devices/system/cpu/vulner <<
522 /sys/devices/system/cpu/vulner <<
523 /sys/devices/system/cpu/vulner <<
524 /sys/devices/system/cpu/vulner <<
525 /sys/devices/system/cpu/vulner <<
526 Date: January 2018 <<
527 Contact: Linux kernel mailing list <linu <<
528 Description: Information about CPU vulnerab <<
529 <<
530 The files are named after the <<
531 vulnerabilities. The output of <<
532 state of the CPUs in the syste <<
533 <<
534 ================ ============ <<
535 "Not affected" CPU is not a <<
536 "Vulnerable" CPU is affec <<
537 "Mitigation: $M" CPU is affec <<
538 ================ ============ <<
539 <<
540 See also: Documentation/admin- <<
541 <<
542 What: /sys/devices/system/cpu/smt <<
543 /sys/devices/system/cpu/smt/ac <<
544 /sys/devices/system/cpu/smt/co <<
545 Date: June 2018 <<
546 Contact: Linux kernel mailing list <linu <<
547 Description: Control Symmetric Multi Thread <<
548 <<
549 active: Tells whether SMT is <<
550 <<
551 control: Read/write interface <<
552 values: <<
553 <<
554 ================ ==== <<
555 "on" SMT <<
556 "off" SMT <<
557 "<N>" SMT <<
558 "forceoff" SMT <<
559 "notsupported" SMT <<
560 "notimplemented" SMT <<
561 impl <<
562 ================ ==== <<
563 <<
564 If control status is <<
565 are rejected. Note th <<
566 offline cores. <<
567 <<
568 What: /sys/devices/system/cpu/cpuX/p <<
569 Date: March 2019 <<
570 Contact: linux-pm@vger.kernel.org <<
571 Description: Intel Energy and Performance B <<
572 <<
573 EPB for the given CPU in a sli <<
574 of 0 corresponds to a hint pre <<
575 and a value of 15 corresponds <<
576 <<
577 In order to change the EPB val <<
578 a number in the 0 - 15 sliding <<
579 strings: "performance", "balan <<
580 "balance-power", "power" (that <<
581 their meaning), to this attrib <<
582 <<
583 This attribute is present for <<
584 Intel EPB feature. <<
585 <<
586 What: /sys/devices/system/cpu/umwait <<
587 /sys/devices/system/cpu/umwait <<
588 /sys/devices/system/cpu/umwait <<
589 Date: May 2019 <<
590 Contact: Linux kernel mailing list <linu <<
591 Description: Umwait control <<
592 <<
593 enable_c02: Read/write interfa <<
594 Read returns C0.2 stat <<
595 0: C0.2 is dis <<
596 1: C0.2 is ena <<
597 <<
598 Write 'y' or '1' or ' <<
599 Write 'n' or '0' or ' <<
600 <<
601 The interface is case <<
602 <<
603 max_time: Read/write interface <<
604 in TSC-quanta that t <<
605 or C0.2 state. The t <<
606 Note that a value of <<
607 Low order two bits m <<
608 <<
609 What: /sys/devices/system/cpu/sev <<
610 /sys/devices/system/cpu/sev/vm <<
611 Date: May 2024 <<
612 Contact: Linux kernel mailing list <linu <<
613 Description: Secure Encrypted Virtualizatio <<
614 <<
615 This directory is only present <<
616 <<
617 vmpl: Reports the Virtual Mach <<
618 the SEV-SNP guest is run <<
619 <<
620 <<
621 What: /sys/devices/system/cpu/svm <<
622 Date: August 2019 <<
623 Contact: Linux kernel mailing list <linu <<
624 Linux for PowerPC mailing list< <<
625 Description: Secure Virtual Machine <<
626 <<
627 If 1, it means the system is u <<
628 Facility in POWER9 and newer p <<
629 Virtual Machine. <<
630 <<
631 What: /sys/devices/system/cpu/cpuX/p <<
632 Date: Apr 2005 <<
633 Contact: Linux for PowerPC mailing list< <<
634 Description: PURR ticks for this CPU since <<
635 <<
636 The Processor Utilization Reso <<
637 a 64-bit counter which provide <<
638 resources used by the CPU thre <<
639 register increases monotonical <<
640 exposes the number of PURR tic <<
641 <<
642 What: /sys/devices/system/cpu/cpuX/s <<
643 Date: Dec 2006 <<
644 Contact: Linux for PowerPC mailing list< <<
645 Description: SPURR ticks for this CPU since <<
646 <<
647 The Scaled Processor Utilizati <<
648 (SPURR) is a 64-bit counter th <<
649 invariant estimate of the reso <<
650 thread. The contents of this r <<
651 monotonically. This sysfs inte <<
652 of SPURR ticks for cpuX. <<
653 <<
654 What: /sys/devices/system/cpu/cpuX/i <<
655 Date: Apr 2020 <<
656 Contact: Linux for PowerPC mailing list< <<
657 Description: PURR ticks for cpuX when it wa <<
658 <<
659 This sysfs interface exposes t <<
660 for cpuX when it was idle. <<
661 <<
662 What: /sys/devices/system/cpu/cpuX/i <<
663 Date: Apr 2020 <<
664 Contact: Linux for PowerPC mailing list< <<
665 Description: SPURR ticks for cpuX when it w <<
666 <<
667 This sysfs interface exposes t <<
668 for cpuX when it was idle. <<
669 <<
670 What: /sys/devices/system/cpu/cpuX/m <<
671 Date: July 2021 <<
672 Contact: Linux ARM Kernel Mailing list < <<
673 Description: Preferred MTE tag checking mod <<
674 <<
675 When a user program specifies <<
676 mode, this sysfs node is used <<
677 be preferred when scheduling a <<
678 values: <<
679 <<
680 ================ ============ <<
681 "sync" Prefer synch <<
682 "asymm" Prefer asymm <<
683 "async" Prefer async <<
684 ================ ============ <<
685 <<
686 See also: Documentation/arch/a <<
687 <<
688 What: /sys/devices/system/cpu/nohz_f <<
689 Date: Apr 2015 <<
690 Contact: Linux kernel mailing list <linu <<
691 Description: <<
692 (RO) the list of CPUs that are <<
693 These CPUs are set by boot par <<
694 <<
695 What: /sys/devices/system/cpu/isolat <<
696 Date: Apr 2015 <<
697 Contact: Linux kernel mailing list <linu <<
698 Description: <<
699 (RO) the list of CPUs that are <<
700 participate in load balancing. <<
701 boot parameter "isolcpus=". <<
702 <<
703 What: /sys/devices/system/cpu/crash_ <<
704 Date: Aug 2023 <<
705 Contact: Linux kernel mailing list <linu <<
706 Description: <<
707 (RO) indicates whether or not <<
708 segments on memory hot un/plug <<
709 need to reload kdump kernel. <<
710 <<
711 What: /sys/devices/system/cpu/enable <<
712 Date: Nov 2022 <<
713 Contact: Linux kernel mailing list <linu <<
714 Description: <<
715 (RO) the list of CPUs that can <<
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