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Linux 6.18.37 · ABI / testing

System CPU sysfs ABI

CPU hotplug·topology, idle/frequency policy, cache, throttling, architecture registers, vulnerabilities·SMT, power hints, virtualization, utilization counters와 isolation 상태를 설명합니다.

Source pathDocumentation/ABI/testing/sysfs-devices-system-cpu
Source versionLinux v6.18.37
TranslationDUJINLABS 전문 번역 + 해설

요약·해설과 원문, 전문 번역을 서로 분리했습니다. API 이름, symbol, source path는 원문 표기를 사용합니다.

1. 요약·해설

원문의 핵심 논리와 kernel programming 관점의 보충 설명입니다. 아래의 전문 번역과는 별도로 작성했습니다.

CPU hierarchy, hotplug and topology

sysfs-devices-system-cpu:1-109

Global CPU directory와 logical CPU instances, online/offline/possible/present masks, architecture-specific probe/release, NUMA node 및 package/core/thread topology를 제공합니다.

CPU idle policy and state statistics

sysfs-devices-system-cpu:110-245

cpuidle driver·governor를 선택하고 state별 latency, power, time, usage, target residency, disable/default status와 suspend-to-idle 통계를 제공합니다.

CPU frequency and performance policy

sysfs-devices-system-cpu:246-399

Clock scaling, shared frequency domain, CPPC autonomous selection/activity window/EPP, system boost와 Intel P-state percentage·turbo limits를 제어합니다.

CPU cache controls and identity

sysfs-devices-system-cpu:331-350, 400-473

AMD L3 index disable slots와 cache allocation/write policy, geometry, sharing, type, size 및 non-contiguous instance ID를 설명합니다.

Throttle statistics, registers and capacity

sysfs-devices-system-cpu:364-375, 474-571

Per-CPU crash notes, POWERNV throttle reasons, AArch64 identification registers, AArch32-capable CPU mask와 heterogeneous CPU capacity를 expose합니다.

Vulnerability status and SMT control

sysfs-devices-system-cpu:572-631

Named CPU vulnerability files는 영향·mitigation state를 보고하고 SMT active/control은 enable, thread count, forced disable와 architecture support 상태를 제어합니다.

Energy hints, UMWAIT and secure virtualization

sysfs-devices-system-cpu:632-694

Intel EPB와 UMWAIT C0.2/max-time policy를 제어하고 AMD SEV-SNP VMPL 및 POWER9 Protected Execution Facility 사용 여부를 보고합니다.

PowerPC utilization counters and ARM MTE

sysfs-devices-system-cpu:695-751

PowerPC PURR/SPURR와 idle variants는 thread resource ticks를 보고하고 ARM64 MTE는 CPU별 preferred tag-checking mode를 선택합니다.

CPU isolation, crash hotplug and online eligibility

sysfs-devices-system-cpu:752-779

Boot parameter로 정한 nohz_full·isolated CPU 목록, kexec segment hotplug update 지원 여부와 online 전환 가능한 CPU 목록을 제공합니다.

2. 영어 원문 전체

번역 기준이 된 Linux v6.18.37 원문입니다. 줄 번호는 이 버전의 파일 좌표입니다.

원문 전체 펼치기
1 What: /sys/devices/system/cpu/
2 Date: pre-git history
3 Contact: Linux kernel mailing list <[email protected]>
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/cpuX/
11
12 What: /sys/devices/system/cpu/kernel_max
13 /sys/devices/system/cpu/offline
14 /sys/devices/system/cpu/online
15 /sys/devices/system/cpu/possible
16 /sys/devices/system/cpu/present
17 Date: December 2008
18 Contact: Linux kernel mailing list <[email protected]>
19 Description: CPU topology files that describe kernel limits related to
20 hotplug. Briefly:
21
22 kernel_max: the maximum cpu index allowed by the kernel
23 configuration.
24
25 offline: cpus that are not online because they have been
26 HOTPLUGGED off or exceed the limit of cpus allowed by the
27 kernel configuration (kernel_max above).
28
29 online: cpus that are online and being scheduled.
30
31 possible: cpus that have been allocated resources and can be
32 brought online if they are present.
33
34 present: cpus that have been identified as being present in
35 the system.
36
37 See Documentation/admin-guide/cputopology.rst for more information.
38
39
40 What: /sys/devices/system/cpu/probe
41 /sys/devices/system/cpu/release
42 Date: November 2009
43 Contact: Linux kernel mailing list <[email protected]>
44 Description: Dynamic addition and removal of CPU's. This is not hotplug
45 removal, this is meant complete removal/addition of the CPU
46 from the system.
47
48 probe: writes to this file will dynamically add a CPU to the
49 system. Information written to the file to add CPU's is
50 architecture specific.
51
52 release: writes to this file dynamically remove a CPU from
53 the system. Information written to the file to remove CPU's
54 is architecture specific.
55
56 What: /sys/devices/system/cpu/cpuX/node
57 Date: October 2009
58 Contact: Linux memory management mailing list <[email protected]>
59 Description: Discover NUMA node a CPU belongs to
60
61 When CONFIG_NUMA is enabled, a symbolic link that points
62 to the corresponding NUMA node directory.
63
64 For example, the following symlink is created for cpu42
65 in NUMA node 2:
66
67 /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
68
69
70 What: /sys/devices/system/cpu/cpuX/topology/core_siblings
71 /sys/devices/system/cpu/cpuX/topology/core_siblings_list
72 /sys/devices/system/cpu/cpuX/topology/physical_package_id
73 /sys/devices/system/cpu/cpuX/topology/thread_siblings
74 /sys/devices/system/cpu/cpuX/topology/thread_siblings_list
75 /sys/devices/system/cpu/cpuX/topology/ppin
76 Date: December 2008
77 Contact: Linux kernel mailing list <[email protected]>
78 Description: CPU topology files that describe a logical CPU's relationship
79 to other cores and threads in the same physical package.
80
81 One cpuX directory is created per logical CPU in the system,
82 e.g. /sys/devices/system/cpu/cpu42/.
83
84 Briefly, the files above are:
85
86 core_siblings: internal kernel map of cpuX's hardware threads
87 within the same physical_package_id.
88
89 core_siblings_list: human-readable list of the logical CPU
90 numbers within the same physical_package_id as cpuX.
91
92 physical_package_id: physical package id of cpuX. Typically
93 corresponds to a physical socket number, but the actual value
94 is architecture and platform dependent.
95
96 thread_siblings: internal kernel map of cpuX's hardware
97 threads within the same core as cpuX
98
99 thread_siblings_list: human-readable list of cpuX's hardware
100 threads within the same core as cpuX
101
102 ppin: human-readable Protected Processor Identification
103 Number of the socket the cpu# belongs to. There should be
104 one per physical_package_id. File is readable only to
105 admin.
106
107 See Documentation/admin-guide/cputopology.rst for more information.
108
109
110 What: /sys/devices/system/cpu/cpuidle/available_governors
111 /sys/devices/system/cpu/cpuidle/current_driver
112 /sys/devices/system/cpu/cpuidle/current_governor
113 /sys/devices/system/cpu/cpuidle/current_governer_ro
114 /sys/devices/system/cpu/cpuidle/intel_c1_demotion
115 Date: September 2007
116 Contact: Linux kernel mailing list <[email protected]>
117 Description: Discover cpuidle policy and mechanism
118
119 Various CPUs today support multiple idle levels that are
120 differentiated by varying exit latencies and power
121 consumption during idle.
122
123 Idle policy (governor) is differentiated from idle mechanism
124 (driver).
125
126 available_governors: (RO) displays a space separated list of
127 available governors.
128
129 current_driver: (RO) displays current idle mechanism.
130
131 current_governor: (RW) displays current idle policy. Users can
132 switch the governor at runtime by writing to this file.
133
134 current_governor_ro: (RO) displays current idle policy.
135
136 intel_c1_demotion: (RW) enables/disables the C1 demotion
137 feature on Intel CPUs.
138
139 See Documentation/admin-guide/pm/cpuidle.rst,
140 Documentation/admin-guide/pm/intel_idle.rst, and
141 Documentation/driver-api/pm/cpuidle.rst for more information.
142
143
144 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/name
145 /sys/devices/system/cpu/cpuX/cpuidle/stateN/latency
146 /sys/devices/system/cpu/cpuX/cpuidle/stateN/power
147 /sys/devices/system/cpu/cpuX/cpuidle/stateN/time
148 /sys/devices/system/cpu/cpuX/cpuidle/stateN/usage
149 /sys/devices/system/cpu/cpuX/cpuidle/stateN/above
150 /sys/devices/system/cpu/cpuX/cpuidle/stateN/below
151 Date: September 2007
152 KernelVersion: v2.6.24
153 Contact: Linux power management list <[email protected]>
154 Description:
155 The directory /sys/devices/system/cpu/cpuX/cpuidle contains per
156 logical CPU specific cpuidle information for each online cpu X.
157 The processor idle states which are available for use have the
158 following attributes:
159
160 ======== ==== =================================================
161 name: (RO) Name of the idle state (string).
162
163 latency: (RO) The latency to exit out of this idle state (in
164 microseconds).
165
166 power: (RO) The power consumed while in this idle state (in
167 milliwatts).
168
169 time: (RO) The total time spent in this idle state
170 (in microseconds).
171
172 usage: (RO) Number of times this state was entered (a count).
173
174 above: (RO) Number of times this state was entered, but the
175 observed CPU idle duration was too short for it
176 (a count).
177
178 below: (RO) Number of times this state was entered, but the
179 observed CPU idle duration was too long for it
180 (a count).
181 ======== ==== =================================================
182
183 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/desc
184 Date: February 2008
185 KernelVersion: v2.6.25
186 Contact: Linux power management list <[email protected]>
187 Description:
188 (RO) A small description about the idle state (string).
189
190
191 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/disable
192 Date: March 2012
193 KernelVersion: v3.10
194 Contact: Linux power management list <[email protected]>
195 Description:
196 (RW) Option to disable this idle state (bool). The behavior and
197 the effect of the disable variable depends on the implementation
198 of a particular governor. In the ladder governor, for example,
199 it is not coherent, i.e. if one is disabling a light state, then
200 all deeper states are disabled as well, but the disable variable
201 does not reflect it. Likewise, if one enables a deep state but a
202 lighter state still is disabled, then this has no effect.
203
204 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/default_status
205 Date: December 2019
206 KernelVersion: v5.6
207 Contact: Linux power management list <[email protected]>
208 Description:
209 (RO) The default status of this state, "enabled" or "disabled".
210
211 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/residency
212 Date: March 2014
213 KernelVersion: v3.15
214 Contact: Linux power management list <[email protected]>
215 Description:
216 (RO) Display the target residency i.e. the minimum amount of
217 time (in microseconds) this cpu should spend in this idle state
218 to make the transition worth the effort.
219
220 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/
221 Date: March 2018
222 KernelVersion: v4.17
223 Contact: Linux power management list <[email protected]>
224 Description:
225 Idle state usage statistics related to suspend-to-idle.
226
227 This attribute group is only present for states that can be
228 used in suspend-to-idle with suspended timekeeping.
229
230 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/time
231 Date: March 2018
232 KernelVersion: v4.17
233 Contact: Linux power management list <[email protected]>
234 Description:
235 Total time spent by the CPU in suspend-to-idle (with scheduler
236 tick suspended) after requesting this state.
237
238 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/usage
239 Date: March 2018
240 KernelVersion: v4.17
241 Contact: Linux power management list <[email protected]>
242 Description:
243 Total number of times this state has been requested by the CPU
244 while entering suspend-to-idle.
245
246 What: /sys/devices/system/cpu/cpuX/cpufreq/*
247 Date: pre-git history
249 Description: Discover and change clock speed of CPUs
250
251 Clock scaling allows you to change the clock speed of the
252 CPUs on the fly. This is a nice method to save battery
253 power, because the lower the clock speed, the less power
254 the CPU consumes.
255
256 There are many knobs to tweak in this directory.
257
258 See files in Documentation/cpu-freq/ for more information.
259
260
261 What: /sys/devices/system/cpu/cpuX/cpufreq/freqdomain_cpus
262 Date: June 2013
264 Description: Discover CPUs in the same CPU frequency coordination domain
265
266 freqdomain_cpus is the list of CPUs (online+offline) that share
267 the same clock/freq domain (possibly at the hardware level).
268 That information may be hidden from the cpufreq core and the
269 value of related_cpus may be different from freqdomain_cpus. This
270 attribute is useful for user space DVFS controllers to get better
271 power/performance results for platforms using acpi-cpufreq.
272
273 This file is only present if the acpi-cpufreq or the cppc-cpufreq
274 drivers are in use.
275
276 What: /sys/devices/system/cpu/cpuX/cpufreq/auto_select
277 Date: May 2025
279 Description: Autonomous selection enable
280
281 Read/write interface to control autonomous selection enable
282 Read returns autonomous selection status:
283 0: autonomous selection is disabled
284 1: autonomous selection is enabled
285
286 Write 'y' or '1' or 'on' to enable autonomous selection.
287 Write 'n' or '0' or 'off' to disable autonomous selection.
288
289 This file is only present if the cppc-cpufreq driver is in use.
290
291 What: /sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
292 Date: May 2025
294 Description: Autonomous activity window
295
296 This file indicates a moving utilization sensitivity window to
297 the platform's autonomous selection policy.
298
299 Read/write an integer represents autonomous activity window (in
300 microseconds) from/to this file. The max value to write is
301 1270000000 but the max significand is 127. This means that if 128
302 is written to this file, 127 will be stored. If the value is
303 greater than 130, only the first two digits will be saved as
304 significand.
305
306 Writing a zero value to this file enable the platform to
307 determine an appropriate Activity Window depending on the workload.
308
309 Writing to this file only has meaning when Autonomous Selection is
310 enabled.
311
312 This file is only present if the cppc-cpufreq driver is in use.
313
314 What: /sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference_val
315 Date: May 2025
317 Description: Energy performance preference
318
319 Read/write an 8-bit integer from/to this file. This file
320 represents a range of values from 0 (performance preference) to
321 0xFF (energy efficiency preference) that influences the rate of
322 performance increase/decrease and the result of the hardware's
323 energy efficiency and performance optimization policies.
324
325 Writing to this file only has meaning when Autonomous Selection is
326 enabled.
327
328 This file is only present if the cppc-cpufreq driver is in use.
329
330
331 What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
332 Date: August 2008
333 KernelVersion: 2.6.27
334 Contact: Linux kernel mailing list <[email protected]>
335 Description: Disable L3 cache indices
336
337 These files exist in every CPU's cache/index3 directory. Each
338 cache_disable_{0,1} file corresponds to one disable slot which
339 can be used to disable a cache index. Reading from these files
340 on a processor with this functionality will return the currently
341 disabled index for that node. There is one L3 structure per
342 node, or per internal node on MCM machines. Writing a valid
343 index to one of these files will cause the specified cache
344 index to be disabled.
345
346 All AMD processors with L3 caches provide this functionality.
347 For details, see BKDGs at
348 https://www.amd.com/en/support/tech-docs?keyword=bios+kernel
349
350
351 What: /sys/devices/system/cpu/cpufreq/boost
352 Date: August 2012
353 Contact: Linux kernel mailing list <[email protected]>
354 Description: Processor frequency boosting control
355
356 This switch controls the boost setting for the whole system.
357 Boosting allows the CPU and the firmware to run at a frequency
358 beyond its nominal limit.
359
360 More details can be found in
361 Documentation/admin-guide/pm/cpufreq.rst
362
363
364 What: /sys/devices/system/cpu/cpuX/crash_notes
365 /sys/devices/system/cpu/cpuX/crash_notes_size
366 Date: April 2013
368 Description: address and size of the percpu note.
369
370 crash_notes: the physical address of the memory that holds the
371 note of cpuX.
372
373 crash_notes_size: size of the note of cpuX.
374
375
376 What: /sys/devices/system/cpu/intel_pstate/max_perf_pct
377 /sys/devices/system/cpu/intel_pstate/min_perf_pct
378 /sys/devices/system/cpu/intel_pstate/no_turbo
379 Date: February 2013
381 Description: Parameters for the Intel P-state driver
382
383 Logic for selecting the current P-state in Intel
384 Sandybridge+ processors. The three knobs control
385 limits for the P-state that will be requested by the
386 driver.
387
388 max_perf_pct: limits the maximum P state that will be requested by
389 the driver stated as a percentage of the available performance.
390
391 min_perf_pct: limits the minimum P state that will be requested by
392 the driver stated as a percentage of the available performance.
393
394 no_turbo: limits the driver to selecting P states below the turbo
395 frequency range.
396
397 More details can be found in
398 Documentation/admin-guide/pm/intel_pstate.rst
399
400 What: /sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
401 Date: July 2014(documented, existed before August 2008)
402 Contact: Sudeep Holla <[email protected]>
403 Linux kernel mailing list <[email protected]>
404 Description: Parameters for the CPU cache attributes
405
406 allocation_policy:
407 - WriteAllocate:
408 allocate a memory location to a cache line
409 on a cache miss because of a write
410 - ReadAllocate:
411 allocate a memory location to a cache line
412 on a cache miss because of a read
413 - ReadWriteAllocate:
414 both writeallocate and readallocate
415
416 coherency_line_size:
417 the minimum amount of data in bytes that gets
418 transferred from memory to cache
419
420 level:
421 the cache hierarchy in the multi-level cache configuration
422
423 number_of_sets:
424 total number of sets in the cache, a set is a
425 collection of cache lines with the same cache index
426
427 physical_line_partition:
428 number of physical cache line per cache tag
429
430 shared_cpu_list:
431 the list of logical cpus sharing the cache
432
433 shared_cpu_map:
434 logical cpu mask containing the list of cpus sharing
435 the cache
436
437 size:
438 the total cache size in kB
439
440 type:
441 - Instruction: cache that only holds instructions
442 - Data: cache that only caches data
443 - Unified: cache that holds both data and instructions
444
445 ways_of_associativity:
446 degree of freedom in placing a particular block
447 of memory in the cache
448
449 write_policy:
450 - WriteThrough:
451 data is written to both the cache line
452 and to the block in the lower-level memory
453 - WriteBack:
454 data is written only to the cache line and
455 the modified cache line is written to main
456 memory only when it is replaced
457
458
459 What: /sys/devices/system/cpu/cpu*/cache/index*/id
460 Date: September 2016
461 Contact: Linux kernel mailing list <[email protected]>
462 Description: Cache id
463
464 The id provides a unique number for a specific instance of
465 a cache of a particular type. E.g. there may be a level
466 3 unified cache on each socket in a server and we may
467 assign them ids 0, 1, 2, ...
468
469 Note that id value can be non-contiguous. E.g. level 1
470 caches typically exist per core, but there may not be a
471 power of two cores on a socket, so these caches may be
472 numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...
473
474 What: /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats
475 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
476 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat
477 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
478 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
479 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
480 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
481 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
482 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
483 Date: March 2016
484 Contact: Linux kernel mailing list <[email protected]>
485 Linux for PowerPC mailing list <[email protected]>
486 Description: POWERNV CPUFreq driver's frequency throttle stats directory and
487 attributes
488
489 'cpuX/cpufreq/throttle_stats' directory contains the CPU frequency
490 throttle stat attributes for the chip. The throttle stats of a cpu
491 is common across all the cpus belonging to a chip. Below are the
492 throttle attributes exported in the 'throttle_stats' directory:
493
494 - turbo_stat : This file gives the total number of times the max
495 frequency is throttled to lower frequency in turbo (at and above
496 nominal frequency) range of frequencies.
497
498 - sub_turbo_stat : This file gives the total number of times the
499 max frequency is throttled to lower frequency in sub-turbo(below
500 nominal frequency) range of frequencies.
501
502 - unthrottle : This file gives the total number of times the max
503 frequency is unthrottled after being throttled.
504
505 - powercap : This file gives the total number of times the max
506 frequency is throttled due to 'Power Capping'.
507
508 - overtemp : This file gives the total number of times the max
509 frequency is throttled due to 'CPU Over Temperature'.
510
511 - supply_fault : This file gives the total number of times the
512 max frequency is throttled due to 'Power Supply Failure'.
513
514 - overcurrent : This file gives the total number of times the
515 max frequency is throttled due to 'Overcurrent'.
516
517 - occ_reset : This file gives the total number of times the max
518 frequency is throttled due to 'OCC Reset'.
519
520 The sysfs attributes representing different throttle reasons like
521 powercap, overtemp, supply_fault, overcurrent and occ_reset map to
522 the reasons provided by OCC firmware for throttling the frequency.
523
524 What: /sys/devices/system/cpu/cpufreq/policyX/throttle_stats
525 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat
526 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat
527 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle
528 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap
529 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp
530 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault
531 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent
532 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
533 Date: March 2016
534 Contact: Linux kernel mailing list <[email protected]>
535 Linux for PowerPC mailing list <[email protected]>
536 Description: POWERNV CPUFreq driver's frequency throttle stats directory and
537 attributes
538
539 'policyX/throttle_stats' directory and all the attributes are same as
540 the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
541 attributes which give the frequency throttle information of the chip.
542
543 What: /sys/devices/system/cpu/cpuX/regs/
544 /sys/devices/system/cpu/cpuX/regs/identification/
545 /sys/devices/system/cpu/cpuX/regs/identification/midr_el1
546 /sys/devices/system/cpu/cpuX/regs/identification/revidr_el1
547 /sys/devices/system/cpu/cpuX/regs/identification/aidr_el1
548 /sys/devices/system/cpu/cpuX/regs/identification/smidr_el1
549 Date: June 2016
550 Contact: Linux ARM Kernel Mailing list <[email protected]>
551 Description: AArch64 CPU registers
552
553 'identification' directory exposes the CPU ID registers for
554 identifying model and revision of the CPU and SMCU.
555
556 What: /sys/devices/system/cpu/aarch32_el0
557 Date: May 2021
558 Contact: Linux ARM Kernel Mailing list <[email protected]>
559 Description: Identifies the subset of CPUs in the system that can execute
560 AArch32 (32-bit ARM) applications. If present, the same format as
561 /sys/devices/system/cpu/{offline,online,possible,present} is used.
562 If absent, then all or none of the CPUs can execute AArch32
563 applications and execve() will behave accordingly.
564
565 What: /sys/devices/system/cpu/cpuX/cpu_capacity
566 Date: December 2016
567 Contact: Linux kernel mailing list <[email protected]>
568 Description: information about CPUs heterogeneity.
569
570 cpu_capacity: capacity of cpuX.
571
572 What: /sys/devices/system/cpu/vulnerabilities
573 /sys/devices/system/cpu/vulnerabilities/gather_data_sampling
574 /sys/devices/system/cpu/vulnerabilities/indirect_target_selection
575 /sys/devices/system/cpu/vulnerabilities/itlb_multihit
576 /sys/devices/system/cpu/vulnerabilities/l1tf
577 /sys/devices/system/cpu/vulnerabilities/mds
578 /sys/devices/system/cpu/vulnerabilities/meltdown
579 /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
580 /sys/devices/system/cpu/vulnerabilities/old_microcode
581 /sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling
582 /sys/devices/system/cpu/vulnerabilities/retbleed
583 /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
584 /sys/devices/system/cpu/vulnerabilities/spectre_v1
585 /sys/devices/system/cpu/vulnerabilities/spectre_v2
586 /sys/devices/system/cpu/vulnerabilities/srbds
587 /sys/devices/system/cpu/vulnerabilities/tsa
588 /sys/devices/system/cpu/vulnerabilities/tsx_async_abort
589 /sys/devices/system/cpu/vulnerabilities/vmscape
590 Date: January 2018
591 Contact: Linux kernel mailing list <[email protected]>
592 Description: Information about CPU vulnerabilities
593
594 The files are named after the code names of CPU
595 vulnerabilities. The output of those files reflects the
596 state of the CPUs in the system. Possible output values:
597
598 ================ ==============================================
599 "Not affected" CPU is not affected by the vulnerability
600 "Vulnerable" CPU is affected and no mitigation in effect
601 "Mitigation: $M" CPU is affected and mitigation $M is in effect
602 ================ ==============================================
603
604 See also: Documentation/admin-guide/hw-vuln/index.rst
605
606 What: /sys/devices/system/cpu/smt
607 /sys/devices/system/cpu/smt/active
608 /sys/devices/system/cpu/smt/control
609 Date: June 2018
610 Contact: Linux kernel mailing list <[email protected]>
611 Description: Control Symmetric Multi Threading (SMT)
612
613 active: Tells whether SMT is active (enabled and siblings online)
614
615 control: Read/write interface to control SMT. Possible
616 values:
617
618 ================ =========================================
619 "on" SMT is enabled
620 "off" SMT is disabled
621 "<N>" SMT is enabled with N threads per core.
622 "forceoff" SMT is force disabled. Cannot be changed.
623 "notsupported" SMT is not supported by the CPU
624 "notimplemented" SMT runtime toggling is not
625 implemented for the architecture
626 ================ =========================================
627
628 If control status is "forceoff" or "notsupported" writes
629 are rejected. Note that enabling SMT on PowerPC skips
630 offline cores.
631
632 What: /sys/devices/system/cpu/cpuX/power/energy_perf_bias
633 Date: March 2019
635 Description: Intel Energy and Performance Bias Hint (EPB)
636
637 EPB for the given CPU in a sliding scale 0 - 15, where a value
638 of 0 corresponds to a hint preference for highest performance
639 and a value of 15 corresponds to the maximum energy savings.
640
641 In order to change the EPB value for the CPU, write either
642 a number in the 0 - 15 sliding scale above, or one of the
643 strings: "performance", "balance-performance", "normal",
644 "balance-power", "power" (that represent values reflected by
645 their meaning), to this attribute.
646
647 This attribute is present for all online CPUs supporting the
648 Intel EPB feature.
649
650 What: /sys/devices/system/cpu/umwait_control
651 /sys/devices/system/cpu/umwait_control/enable_c02
652 /sys/devices/system/cpu/umwait_control/max_time
653 Date: May 2019
654 Contact: Linux kernel mailing list <[email protected]>
655 Description: Umwait control
656
657 enable_c02: Read/write interface to control umwait C0.2 state
658 Read returns C0.2 state status:
659 0: C0.2 is disabled
660 1: C0.2 is enabled
661
662 Write 'y' or '1' or 'on' to enable C0.2 state.
663 Write 'n' or '0' or 'off' to disable C0.2 state.
664
665 The interface is case insensitive.
666
667 max_time: Read/write interface to control umwait maximum time
668 in TSC-quanta that the CPU can reside in either C0.1
669 or C0.2 state. The time is an unsigned 32-bit number.
670 Note that a value of zero means there is no limit.
671 Low order two bits must be zero.
672
673 What: /sys/devices/system/cpu/sev
674 /sys/devices/system/cpu/sev/vmpl
675 Date: May 2024
676 Contact: Linux kernel mailing list <[email protected]>
677 Description: Secure Encrypted Virtualization (SEV) information
678
679 This directory is only present when running as an SEV-SNP guest.
680
681 vmpl: Reports the Virtual Machine Privilege Level (VMPL) at which
682 the SEV-SNP guest is running.
683
684
685 What: /sys/devices/system/cpu/svm
686 Date: August 2019
687 Contact: Linux kernel mailing list <[email protected]>
688 Linux for PowerPC mailing list <[email protected]>
689 Description: Secure Virtual Machine
690
691 If 1, it means the system is using the Protected Execution
692 Facility in POWER9 and newer processors. i.e., it is a Secure
693 Virtual Machine.
694
695 What: /sys/devices/system/cpu/cpuX/purr
696 Date: Apr 2005
697 Contact: Linux for PowerPC mailing list <[email protected]>
698 Description: PURR ticks for this CPU since the system boot.
699
700 The Processor Utilization Resources Register (PURR) is
701 a 64-bit counter which provides an estimate of the
702 resources used by the CPU thread. The contents of this
703 register increases monotonically. This sysfs interface
704 exposes the number of PURR ticks for cpuX.
705
706 What: /sys/devices/system/cpu/cpuX/spurr
707 Date: Dec 2006
708 Contact: Linux for PowerPC mailing list <[email protected]>
709 Description: SPURR ticks for this CPU since the system boot.
710
711 The Scaled Processor Utilization Resources Register
712 (SPURR) is a 64-bit counter that provides a frequency
713 invariant estimate of the resources used by the CPU
714 thread. The contents of this register increases
715 monotonically. This sysfs interface exposes the number
716 of SPURR ticks for cpuX.
717
718 What: /sys/devices/system/cpu/cpuX/idle_purr
719 Date: Apr 2020
720 Contact: Linux for PowerPC mailing list <[email protected]>
721 Description: PURR ticks for cpuX when it was idle.
722
723 This sysfs interface exposes the number of PURR ticks
724 for cpuX when it was idle.
725
726 What: /sys/devices/system/cpu/cpuX/idle_spurr
727 Date: Apr 2020
728 Contact: Linux for PowerPC mailing list <[email protected]>
729 Description: SPURR ticks for cpuX when it was idle.
730
731 This sysfs interface exposes the number of SPURR ticks
732 for cpuX when it was idle.
733
734 What: /sys/devices/system/cpu/cpuX/mte_tcf_preferred
735 Date: July 2021
736 Contact: Linux ARM Kernel Mailing list <[email protected]>
737 Description: Preferred MTE tag checking mode
738
739 When a user program specifies more than one MTE tag checking
740 mode, this sysfs node is used to specify which mode should
741 be preferred when scheduling a task on that CPU. Possible
742 values:
743
744 ================ ==============================================
745 "sync" Prefer synchronous mode
746 "asymm" Prefer asymmetric mode
747 "async" Prefer asynchronous mode
748 ================ ==============================================
749
750 See also: Documentation/arch/arm64/memory-tagging-extension.rst
751
752 What: /sys/devices/system/cpu/nohz_full
753 Date: Apr 2015
754 Contact: Linux kernel mailing list <[email protected]>
755 Description:
756 (RO) the list of CPUs that are in nohz_full mode.
757 These CPUs are set by boot parameter "nohz_full=".
758
759 What: /sys/devices/system/cpu/isolated
760 Date: Apr 2015
761 Contact: Linux kernel mailing list <[email protected]>
762 Description:
763 (RO) the list of CPUs that are isolated and don't
764 participate in load balancing. These CPUs are set by
765 boot parameter "isolcpus=".
766
767 What: /sys/devices/system/cpu/crash_hotplug
768 Date: Aug 2023
769 Contact: Linux kernel mailing list <[email protected]>
770 Description:
771 (RO) indicates whether or not the kernel updates relevant kexec
772 segments on memory hot un/plug and/or on/offline events, avoiding the
773 need to reload kdump kernel.
774
775 What: /sys/devices/system/cpu/enabled
776 Date: Nov 2022
777 Contact: Linux kernel mailing list <[email protected]>
778 Description:
779 (RO) the list of CPUs that can be brought online.
780

3. 한국어 전문 번역

영어 원문의 문단 순서와 의미를 유지한 전체 번역입니다. 코드, 함수명, symbol과 URL은 원문 표기를 유지합니다.

Global and per-CPU attribute hierarchy

1-11
항목한국어 전문 번역
What/sys/devices/system/cpu/
Datepre-git history
ContactLinux kernel mailing list <[email protected]>
DescriptionGlobal CPU attribute와 개별 CPU attribute를 함께 모아 둔 directory입니다. 개별 CPU attribute는 kernel logical CPU number로 이름 붙인 subdirectory에 들어 있습니다. 예를 들면 /sys/devices/system/cpu/cpuX/입니다.
System CPU sysfs hierarchy
/sys/devices/system/cpu/Global CPU attributescpuX logical CPU directoryPer-CPU topology, idle, frequency and architecture data

Global controls와 logical-CPU-specific attributes가 갈라지는 구조입니다.

CPU hotplug topology masks

12-39
항목한국어 전문 번역
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
Date2008년 12월
ContactLinux kernel mailing list <[email protected]>
DescriptionHotplug와 관련된 kernel limit를 설명하는 CPU topology files입니다. kernel_max는 kernel configuration이 허용하는 maximum CPU index입니다. offline은 hotplug로 off되었거나 kernel_max limit를 초과해 online이 아닌 CPU들입니다. online은 online 상태이며 scheduling 중인 CPU들입니다. possible은 resource가 할당되어 있고 present하면 online으로 전환할 수 있는 CPU들입니다. present는 system에 존재한다고 식별된 CPU들입니다. 자세한 내용은 Documentation/admin-guide/cputopology.rst를 참조하십시오.
CPU availability sets
FileMeaning
kernel_maxMaximum CPU index allowed by configuration
offlinePresent or configured CPUs not currently online
onlineOnline CPUs participating in scheduling
possibleCPUs with resources that may be brought online
presentCPUs identified as physically/logically present

Hotplug lifecycle과 configuration limit 관점의 CPU sets입니다.

Dynamic CPU addition and complete removal

40-55
항목한국어 전문 번역
What/sys/devices/system/cpu/probe; /sys/devices/system/cpu/release
Date2009년 11월
ContactLinux kernel mailing list <[email protected]>
DescriptionCPU를 동적으로 추가하거나 제거합니다. 이는 hotplug removal이 아니라 system에서 CPU를 완전히 제거하거나 추가하기 위한 interface입니다. probe에 architecture-specific 정보를 write하면 CPU가 system에 동적으로 추가됩니다. release에 architecture-specific 정보를 write하면 CPU가 system에서 동적으로 제거됩니다.

CPU NUMA-node link

56-69
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/node
Date2009년 10월
ContactLinux memory management mailing list <[email protected]>
DescriptionCPU가 속한 NUMA node를 찾는 interface입니다. CONFIG_NUMA가 enable되어 있으면 해당 NUMA node directory를 가리키는 symbolic link가 생성됩니다. 예를 들어 NUMA node 2에 속한 cpu42에는 /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2 link가 만들어집니다.
CPU-to-NUMA mapping
/sys/devices/system/cpu/cpu42/node2Symbolic link../../node/node2NUMA node 2

Per-CPU directory의 symlink가 canonical node directory를 가리킵니다.

Package, core and thread topology

70-109
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/topology/core_siblings; /sys/devices/system/cpu/cpuX/topology/core_siblings_list; /sys/devices/system/cpu/cpuX/topology/physical_package_id; /sys/devices/system/cpu/cpuX/topology/thread_siblings; /sys/devices/system/cpu/cpuX/topology/thread_siblings_list; /sys/devices/system/cpu/cpuX/topology/ppin
Date2008년 12월
ContactLinux kernel mailing list <[email protected]>
DescriptionLogical CPU와 같은 physical package 안의 다른 core 및 thread 사이 관계를 설명하는 topology files입니다. System의 logical CPU마다 cpuX directory가 하나씩 생성됩니다. core_siblings는 cpuX와 physical_package_id가 같은 hardware thread의 internal kernel map이고, core_siblings_list는 같은 package의 logical CPU number를 사람이 읽을 수 있게 나열합니다. physical_package_id는 cpuX의 physical package ID이며 보통 physical socket number에 대응하지만 실제 값은 architecture와 platform에 따라 달라집니다. thread_siblings는 cpuX와 같은 core의 hardware thread를 나타내는 internal kernel map이고, thread_siblings_list는 이를 사람이 읽을 수 있게 나열합니다. ppin은 cpuX가 속한 socket의 Protected Processor Identification Number를 사람이 읽을 수 있게 표시합니다. physical_package_id마다 하나가 있어야 하며 admin만 읽을 수 있습니다. 자세한 내용은 Documentation/admin-guide/cputopology.rst를 참조하십시오.
CPU topology views
AttributeScope / representation
core_siblingsKernel map of threads in same package
core_siblings_listReadable logical CPUs in same package
physical_package_idArchitecture/platform-specific package ID
thread_siblingsKernel map of threads in same core
thread_siblings_listReadable threads in same core
ppinAdmin-only socket Protected Processor ID

Package와 core sharing을 bitmap, list 및 identifier로 표현합니다.

CPU idle driver and governor policy

110-143
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuidle/available_governors; /sys/devices/system/cpu/cpuidle/current_driver; /sys/devices/system/cpu/cpuidle/current_governor; /sys/devices/system/cpu/cpuidle/current_governer_ro; /sys/devices/system/cpu/cpuidle/intel_c1_demotion
Date2007년 9월
ContactLinux kernel mailing list <[email protected]>
DescriptionCpuidle policy와 mechanism을 확인합니다. 오늘날 여러 CPU는 exit latency와 idle power consumption이 다른 복수의 idle level을 지원합니다. Idle policy(governor)는 idle mechanism(driver)과 구분됩니다. available_governors는 사용 가능한 governor를 space-separated list로 표시하는 RO file입니다. current_driver는 현재 idle mechanism을 표시하는 RO file입니다. current_governor는 현재 idle policy를 표시하고 write로 runtime governor를 바꿀 수 있는 RW file입니다. 원문의 What path는 current_governer_ro로 표기되어 있으나 설명에서는 current_governor_ro라 하며, 현재 idle policy를 표시하는 RO file입니다. intel_c1_demotion은 Intel CPU의 C1 demotion 기능을 enable/disable하는 RW file입니다. 자세한 내용은 Documentation/admin-guide/pm/cpuidle.rst, Documentation/admin-guide/pm/intel_idle.rst, Documentation/driver-api/pm/cpuidle.rst를 참조하십시오.
Cpuidle policy interfaces
AttributeModePurpose
available_governorsROAvailable idle policies
current_driverROCurrent idle mechanism
current_governorRWCurrent/selectable idle policy
current_governer_roROCurrent idle policy
intel_c1_demotionRWIntel C1 demotion control

Idle mechanism, policy와 Intel-specific control의 access mode입니다.

Per-state CPU idle statistics

144-182
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/name; /sys/devices/system/cpu/cpuX/cpuidle/stateN/latency; /sys/devices/system/cpu/cpuX/cpuidle/stateN/power; /sys/devices/system/cpu/cpuX/cpuidle/stateN/time; /sys/devices/system/cpu/cpuX/cpuidle/stateN/usage; /sys/devices/system/cpu/cpuX/cpuidle/stateN/above; /sys/devices/system/cpu/cpuX/cpuidle/stateN/below
Date2007년 9월
KernelVersionv2.6.24
ContactLinux power management list <[email protected]>
Description/sys/devices/system/cpu/cpuX/cpuidle directory에는 online logical CPU X마다 CPU별 cpuidle 정보가 들어 있습니다. 사용 가능한 processor idle state는 다음 attribute를 가집니다. name은 idle-state name string, latency는 해당 state에서 빠져나오는 latency(microseconds), power는 해당 state의 power consumption(milliwatts), time은 해당 state에서 보낸 total time(microseconds), usage는 state 진입 횟수입니다. above는 이 state에 진입했지만 관측된 CPU idle duration이 너무 짧았던 횟수이고, below는 진입했지만 관측된 idle duration이 너무 길었던 횟수입니다. 모두 read-only입니다.
Cpuidle state attributes
AttributeModeMeaning / unit
nameROIdle-state name string
latencyROExit latency, microseconds
powerROPower consumption, milliwatts
timeROTotal residency time, microseconds
usageROEntry count
aboveROEntries where observed idle was too short
belowROEntries where observed idle was too long

원문의 ASCII 표를 access mode, value와 unit이 드러나는 구조화 표로 옮겼습니다.

Idle-state description

183-190
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/desc
Date2008년 2월
KernelVersionv2.6.25
ContactLinux power management list <[email protected]>
Description(RO) Idle state에 관한 짧은 description string입니다.

Idle-state disable control

191-203
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/disable
Date2012년 3월
KernelVersionv3.10
ContactLinux power management list <[email protected]>
Description(RW) 해당 idle state를 disable하는 boolean option입니다. disable variable의 behavior와 effect는 governor 구현에 따라 달라집니다. 예를 들어 ladder governor에서는 coherent하지 않습니다. Light state 하나를 disable하면 더 deep한 state도 모두 disable되지만 각 disable variable에는 이 사실이 반영되지 않습니다. 마찬가지로 lighter state가 여전히 disabled인 상태에서 deep state를 enable해도 효과가 없습니다.
Ladder-governor disable effect
Disable a light idle stateAll deeper states become unavailableTheir disable files may not reflect thatRe-enabling only a deeper state has no effect while lighter state stays disabled

Per-state variable과 실제 reachable idle-state chain이 다를 수 있습니다.

Default idle-state status

204-210
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/default_status
Date2019년 12월
KernelVersionv5.6
ContactLinux power management list <[email protected]>
Description(RO) 해당 state의 default status인 "enabled" 또는 "disabled"를 표시합니다.

Idle-state target residency

211-219
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/residency
Date2014년 3월
KernelVersionv3.15
ContactLinux power management list <[email protected]>
Description(RO) Target residency를 표시합니다. 즉 이 idle state로 transition할 가치가 있으려면 CPU가 해당 state에서 보내야 하는 minimum time을 microseconds 단위로 나타냅니다.

Suspend-to-idle state statistics group

220-229
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/
Date2018년 3월
KernelVersionv4.17
ContactLinux power management list <[email protected]>
DescriptionSuspend-to-idle과 관련된 idle-state usage statistics입니다. Timekeeping이 suspended된 suspend-to-idle에서 사용할 수 있는 state에만 이 attribute group이 존재합니다.
Suspend-to-idle accounting scope
Idle state supports suspend-to-idleTimekeeping is suspendedCPU requests state during s2idles2idle/time and s2idle/usage are updated

지원 state에서 scheduler tick이 멈춘 s2idle request만 별도로 집계합니다.

Suspend-to-idle total time

230-237
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/time
Date2018년 3월
KernelVersionv4.17
ContactLinux power management list <[email protected]>
Description이 state를 request한 뒤 CPU가 scheduler tick이 suspended된 suspend-to-idle에서 보낸 total time입니다.

Suspend-to-idle request count

238-245
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/usage
Date2018년 3월
KernelVersionv4.17
ContactLinux power management list <[email protected]>
DescriptionCPU가 suspend-to-idle에 진입하면서 이 state를 request한 total count입니다.

CPU clock-frequency controls

246-260
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/*
Datepre-git history
Contact[email protected]
DescriptionCPU clock speed를 확인하고 변경합니다. Clock scaling을 사용하면 CPU clock speed를 실행 중에 변경할 수 있습니다. Clock speed가 낮을수록 CPU power consumption도 줄어들기 때문에 battery power를 절약하는 좋은 방법입니다. 이 directory에는 조정할 수 있는 많은 knob가 있습니다. 자세한 내용은 Documentation/cpu-freq/ 아래 file을 참조하십시오.

CPU frequency coordination domain

261-275
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/freqdomain_cpus
Date2013년 6월
Contact[email protected]
Description같은 CPU frequency coordination domain의 CPU를 확인합니다. freqdomain_cpus는 같은 clock/frequency domain을 공유하는 online 및 offline CPU 목록이며, hardware level에서 공유할 수도 있습니다. 이 정보는 cpufreq core에 보이지 않을 수 있으므로 related_cpus 값이 freqdomain_cpus와 다를 수 있습니다. 이 attribute는 acpi-cpufreq를 사용하는 platform의 userspace DVFS controller가 더 나은 power/performance 결과를 얻는 데 유용합니다. acpi-cpufreq 또는 cppc-cpufreq driver를 사용할 때만 file이 존재합니다.
Cpufreq CPU sets
AttributeMeaning
related_cpusCPUs related as visible to cpufreq core
freqdomain_cpusOnline + offline CPUs sharing clock/frequency domain

Core-visible policy relation과 hardware coordination domain이 다를 수 있습니다.

CPPC autonomous selection enable

276-290
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/auto_select
Date2025년 5월
Contact[email protected]
DescriptionAutonomous selection enable을 제어하는 read/write interface입니다. Read 결과 0은 autonomous selection disabled, 1은 enabled를 뜻합니다. 'y', '1', 'on'을 write하면 enable하고, 'n', '0', 'off'를 write하면 disable합니다. cppc-cpufreq driver를 사용할 때만 이 file이 존재합니다.
Autonomous-selection values
ActionDisabledEnabled
Read01
Write aliasesn, 0, offy, 1, on

Read status와 accepted write aliases입니다.

CPPC autonomous activity window

291-313
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/auto_act_window
Date2025년 5월
Contact[email protected]
DescriptionPlatform의 autonomous-selection policy에 moving utilization sensitivity window를 알려 줍니다. 이 file에서 microseconds 단위 autonomous activity window를 integer로 read/write합니다. Write 가능한 maximum value는 1270000000이지만 maximum significand는 127입니다. 따라서 128을 write하면 127이 저장됩니다. 값이 130보다 크면 첫 두 digit만 significand로 저장됩니다. 0을 write하면 workload에 따라 적절한 Activity Window를 platform이 결정할 수 있습니다. 이 file에 write하는 동작은 Autonomous Selection이 enabled일 때만 의미가 있습니다. cppc-cpufreq driver를 사용할 때만 file이 존재합니다.
Autonomous activity-window rules
InputResult
0Platform selects an appropriate window
128127 stored because maximum significand is 127
> 130Only first two digits saved as significand
Maximum write1270000000

Microsecond input의 special handling을 원문 규칙대로 정리했습니다.

CPPC energy-performance preference value

314-330
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/energy_performance_preference_val
Date2025년 5월
Contact[email protected]
Description8-bit integer를 read/write하는 file입니다. 0(performance preference)부터 0xFF(energy-efficiency preference)까지의 값을 나타내며 performance 증가·감소 속도와 hardware의 energy-efficiency/performance optimization policy 결과에 영향을 줍니다. 이 file에 write하는 동작은 Autonomous Selection이 enabled일 때만 의미가 있습니다. cppc-cpufreq driver를 사용할 때만 file이 존재합니다.
Energy-performance preference scale
ValuePreference
0Performance
0xFFEnergy efficiency

8-bit range의 양 끝이 나타내는 optimization preference입니다.

AMD L3 cache-index disable slots

331-350
항목한국어 전문 번역
What/sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
Date2008년 8월
KernelVersion2.6.27
ContactLinux kernel mailing list <[email protected]>
DescriptionL3 cache index를 disable합니다. 이 file은 모든 CPU의 cache/index3 directory에 존재합니다. cache_disable_{0,1} file 각각은 cache index 하나를 disable하는 데 쓸 수 있는 disable slot 하나에 대응합니다. 이 기능이 있는 processor에서 file을 읽으면 해당 node에서 현재 disabled인 index를 반환합니다. Node마다 L3 structure가 하나 있으며 MCM machine에서는 internal node마다 하나입니다. Valid index를 write하면 지정한 cache index가 disabled됩니다. L3 cache가 있는 모든 AMD processor가 이 기능을 제공합니다. 자세한 내용은 https://www.amd.com/en/support/tech-docs?keyword=bios+kernel 의 BKDG를 참조하십시오.
L3 cache-index disable slot
Select cache_disable_0 or cache_disable_1Write a valid L3 cache indexNode or MCM internal-node L3 structureSpecified cache index disabled

각 slot은 node-local L3 index 하나를 선택해 disable합니다.

System-wide processor frequency boost

351-363
항목한국어 전문 번역
What/sys/devices/system/cpu/cpufreq/boost
Date2012년 8월
ContactLinux kernel mailing list <[email protected]>
DescriptionProcessor frequency boosting을 제어합니다. 이 switch는 system 전체의 boost setting을 제어합니다. Boosting을 사용하면 CPU와 firmware가 nominal limit를 넘는 frequency에서 실행될 수 있습니다. 자세한 내용은 Documentation/admin-guide/pm/cpufreq.rst를 참조하십시오.

Per-CPU crash-note address and size

364-375
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/crash_notes; /sys/devices/system/cpu/cpuX/crash_notes_size
Date2013년 4월
Contact[email protected]
DescriptionPer-CPU note의 address와 size를 제공합니다. crash_notes는 cpuX의 note를 보관하는 memory의 physical address이고, crash_notes_size는 cpuX note의 size입니다.

Intel P-state performance limits

376-399
항목한국어 전문 번역
What/sys/devices/system/cpu/intel_pstate/max_perf_pct; /sys/devices/system/cpu/intel_pstate/min_perf_pct; /sys/devices/system/cpu/intel_pstate/no_turbo
Date2013년 2월
Contact[email protected]
DescriptionIntel P-state driver parameter입니다. Intel Sandybridge 이상 processor에서 current P-state를 선택하는 logic이며 세 knob가 driver가 request할 P-state limit를 제어합니다. max_perf_pct는 available performance의 percentage로 maximum requested P-state를 제한합니다. min_perf_pct는 available performance의 percentage로 minimum requested P-state를 제한합니다. no_turbo는 driver가 turbo-frequency range 아래의 P-state만 선택하도록 제한합니다. 자세한 내용은 Documentation/admin-guide/pm/intel_pstate.rst를 참조하십시오.
Intel P-state limit knobs
AttributeLimit
max_perf_pctMaximum P-state as available-performance percentage
min_perf_pctMinimum P-state as available-performance percentage
no_turboRestrict selection below turbo range

Requested performance range와 turbo eligibility를 제한합니다.

CPU cache policy, geometry and sharing

400-458
항목한국어 전문 번역
What/sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
Date2014년 7월(documented, 2008년 8월 이전부터 존재)
ContactSudeep Holla <[email protected]>; Linux kernel mailing list <[email protected]>
DescriptionCPU cache attribute parameter입니다. allocation_policy의 WriteAllocate는 write로 인한 cache miss 때 memory location을 cache line에 allocate하고, ReadAllocate는 read miss 때 allocate하며, ReadWriteAllocate는 두 방식을 모두 사용합니다. coherency_line_size는 memory에서 cache로 전송되는 minimum data amount를 bytes로 나타냅니다. level은 multi-level cache configuration의 cache hierarchy level입니다. number_of_sets는 cache의 total set 수이며 set은 같은 cache index를 가진 cache line collection입니다. physical_line_partition은 cache tag 하나당 physical cache line 수입니다. shared_cpu_list는 cache를 공유하는 logical CPU 목록이고 shared_cpu_map은 그 CPU 목록을 담은 logical CPU mask입니다. size는 total cache size(kB)입니다. type은 instruction만 담는 Instruction, data만 cache하는 Data, data와 instruction을 모두 담는 Unified 중 하나입니다. ways_of_associativity는 특정 memory block을 cache에 배치할 수 있는 자유도입니다. write_policy의 WriteThrough는 cache line과 lower-level memory block 모두에 data를 write하고, WriteBack은 cache line에만 write한 뒤 modified line이 교체될 때 main memory에 write합니다.
CPU cache attributes
AttributeMeaning
allocation_policyWriteAllocate, ReadAllocate or ReadWriteAllocate
coherency_line_sizeMinimum transfer size from memory, bytes
levelCache hierarchy level
number_of_setsTotal sets
physical_line_partitionPhysical lines per cache tag
shared_cpu_list / mapReadable list / logical CPU mask sharing cache
sizeTotal cache size in kB
typeInstruction, Data or Unified
ways_of_associativityPlacement freedom for a memory block
write_policyWriteThrough or WriteBack

Cache policy, geometry, sharing과 capacity attributes를 구조화했습니다.

Cache-instance identifier

459-473
항목한국어 전문 번역
What/sys/devices/system/cpu/cpu*/cache/index*/id
Date2016년 9월
ContactLinux kernel mailing list <[email protected]>
Description특정 type의 cache instance 하나에 unique number를 부여합니다. 예를 들어 server의 socket마다 level-3 unified cache가 있다면 ID 0, 1, 2 등을 할당할 수 있습니다. ID 값은 contiguous하지 않을 수 있습니다. Level-1 cache는 보통 core마다 있지만 socket의 core 수가 2의 거듭제곱이 아닐 수 있으므로 0, 1, 2, 3, 4, 5, 8, 9, 10 등으로 번호가 매겨질 수 있습니다.

POWERNV per-chip throttle statistics

474-523
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent; /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
Date2016년 3월
ContactLinux kernel mailing list <[email protected]>; Linux for PowerPC mailing list <[email protected]>
DescriptionPOWERNV CPUFreq driver의 frequency-throttle statistics directory와 attributes입니다. cpuX/cpufreq/throttle_stats에는 chip의 CPU-frequency throttle statistics가 들어 있으며 한 CPU의 statistics는 같은 chip의 모든 CPU에 공통입니다. turbo_stat은 turbo range, 즉 nominal frequency 이상에서 maximum frequency가 lower frequency로 throttle된 total count입니다. sub_turbo_stat은 sub-turbo range, 즉 nominal frequency 아래에서 maximum frequency가 lower frequency로 throttle된 total count입니다. unthrottle은 throttle 뒤 maximum frequency가 unthrottle된 total count입니다. powercap은 Power Capping 때문에, overtemp는 CPU Over Temperature 때문에, supply_fault는 Power Supply Failure 때문에, overcurrent는 Overcurrent 때문에, occ_reset은 OCC Reset 때문에 maximum frequency가 throttle된 total count입니다. powercap, overtemp, supply_fault, overcurrent, occ_reset attributes는 OCC firmware가 제공하는 frequency-throttling reason에 대응합니다.
POWERNV throttle counters
AttributeCounted event
turbo_statThrottle within at/above nominal turbo range
sub_turbo_statThrottle below nominal frequency
unthrottleMaximum frequency restored after throttle
powercapPower-capping throttle
overtempCPU over-temperature throttle
supply_faultPower-supply-failure throttle
overcurrentOvercurrent throttle
occ_resetOCC-reset throttle

Frequency range transition과 OCC firmware reason별 counters입니다.

Policy-view POWERNV throttle statistics

524-542
항목한국어 전문 번역
What/sys/devices/system/cpu/cpufreq/policyX/throttle_stats; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent; /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
Date2016년 3월
ContactLinux kernel mailing list <[email protected]>; Linux for PowerPC mailing list <[email protected]>
DescriptionPOWERNV CPUFreq driver의 frequency-throttle statistics directory와 attributes입니다. policyX/throttle_stats directory 및 모든 attribute는 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory와 동일하며 chip의 frequency-throttle 정보를 제공합니다.

AArch64 CPU identification registers

543-555
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/regs/; /sys/devices/system/cpu/cpuX/regs/identification/; /sys/devices/system/cpu/cpuX/regs/identification/midr_el1; /sys/devices/system/cpu/cpuX/regs/identification/revidr_el1; /sys/devices/system/cpu/cpuX/regs/identification/aidr_el1; /sys/devices/system/cpu/cpuX/regs/identification/smidr_el1
Date2016년 6월
ContactLinux ARM Kernel Mailing list <[email protected]>
DescriptionAArch64 CPU registers입니다. identification directory는 CPU와 SMCU의 model 및 revision을 식별하기 위한 CPU ID registers를 expose합니다.
AArch64 identification-register files
FileDirectory
midr_el1cpuX/regs/identification/
revidr_el1cpuX/regs/identification/
aidr_el1cpuX/regs/identification/
smidr_el1cpuX/regs/identification/

Per-CPU identification directory에서 expose하는 registers입니다.

AArch32 userspace-capable CPU mask

556-564
항목한국어 전문 번역
What/sys/devices/system/cpu/aarch32_el0
Date2021년 5월
ContactLinux ARM Kernel Mailing list <[email protected]>
DescriptionSystem에서 AArch32(32-bit ARM) application을 실행할 수 있는 CPU subset을 식별합니다. File이 존재하면 /sys/devices/system/cpu/{offline,online,possible,present}와 같은 형식을 사용합니다. File이 없으면 모든 CPU 또는 어떤 CPU도 AArch32 application을 실행할 수 없으며 execve()가 그에 맞게 동작합니다.

Heterogeneous CPU capacity

565-571
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/cpu_capacity
Date2016년 12월
ContactLinux kernel mailing list <[email protected]>
DescriptionCPU heterogeneity에 관한 정보입니다. cpu_capacity는 cpuX의 capacity를 나타냅니다.

CPU vulnerability status files

572-605
항목한국어 전문 번역
What/sys/devices/system/cpu/vulnerabilities; /sys/devices/system/cpu/vulnerabilities/gather_data_sampling; /sys/devices/system/cpu/vulnerabilities/indirect_target_selection; /sys/devices/system/cpu/vulnerabilities/itlb_multihit; /sys/devices/system/cpu/vulnerabilities/l1tf; /sys/devices/system/cpu/vulnerabilities/mds; /sys/devices/system/cpu/vulnerabilities/meltdown; /sys/devices/system/cpu/vulnerabilities/mmio_stale_data; /sys/devices/system/cpu/vulnerabilities/old_microcode; /sys/devices/system/cpu/vulnerabilities/reg_file_data_sampling; /sys/devices/system/cpu/vulnerabilities/retbleed; /sys/devices/system/cpu/vulnerabilities/spec_store_bypass; /sys/devices/system/cpu/vulnerabilities/spectre_v1; /sys/devices/system/cpu/vulnerabilities/spectre_v2; /sys/devices/system/cpu/vulnerabilities/srbds; /sys/devices/system/cpu/vulnerabilities/tsa; /sys/devices/system/cpu/vulnerabilities/tsx_async_abort; /sys/devices/system/cpu/vulnerabilities/vmscape
Date2018년 1월
ContactLinux kernel mailing list <[email protected]>
DescriptionCPU vulnerability 정보를 제공합니다. File은 CPU vulnerability code name으로 이름 붙이며 output은 system CPU의 상태를 반영합니다. "Not affected"는 CPU가 해당 vulnerability의 영향을 받지 않음을, "Vulnerable"은 영향을 받으며 mitigation이 적용되지 않았음을, "Mitigation: $M"은 영향을 받지만 mitigation $M이 적용 중임을 뜻합니다. 자세한 내용은 Documentation/admin-guide/hw-vuln/index.rst도 참조하십시오.
CPU vulnerability outputs
OutputMeaning
Not affectedCPU is not affected
VulnerableAffected with no mitigation in effect
Mitigation: $MAffected with mitigation $M in effect

원문의 ASCII status table을 구조화했습니다.

Symmetric Multi-Threading control

606-631
항목한국어 전문 번역
What/sys/devices/system/cpu/smt; /sys/devices/system/cpu/smt/active; /sys/devices/system/cpu/smt/control
Date2018년 6월
ContactLinux kernel mailing list <[email protected]>
DescriptionSymmetric Multi Threading(SMT)을 제어합니다. active는 SMT가 active한지, 즉 enabled이며 sibling이 online인지 알려 줍니다. control은 SMT를 제어하는 read/write interface입니다. "on"은 SMT enabled, "off"는 disabled, "<N>"은 core당 N thread로 SMT enabled를 뜻합니다. "forceoff"는 변경할 수 없는 forced-disabled 상태, "notsupported"는 CPU가 SMT를 지원하지 않음, "notimplemented"는 architecture가 runtime SMT toggle을 구현하지 않았음을 뜻합니다. control status가 "forceoff" 또는 "notsupported"이면 write가 거부됩니다. PowerPC에서 SMT를 enable할 때는 offline core를 건너뜁니다.
SMT control states
ValueMeaning / mutability
onSMT enabled
offSMT disabled
<N>Enabled with N threads per core
forceoffForced disabled; cannot be changed
notsupportedCPU does not support SMT; writes rejected
notimplementedArchitecture lacks runtime toggling

원문의 ASCII control-value table과 write restrictions입니다.

Intel Energy and Performance Bias Hint

632-649
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/power/energy_perf_bias
Date2019년 3월
Contact[email protected]
Description해당 CPU의 Intel Energy and Performance Bias Hint(EPB)입니다. 0부터 15까지의 sliding scale에서 0은 highest-performance preference, 15는 maximum energy savings에 해당합니다. CPU의 EPB를 바꾸려면 0-15 숫자 또는 의미를 반영하는 "performance", "balance-performance", "normal", "balance-power", "power" string 중 하나를 write합니다. Intel EPB 기능을 지원하는 모든 online CPU에 이 attribute가 존재합니다.
Intel EPB preference scale
InputPreference
0 / performanceHighest performance
balance-performanceBalanced toward performance
normalNeutral
balance-powerBalanced toward power saving
15 / powerMaximum energy savings

Numeric endpoint와 accepted semantic aliases입니다.

UMWAIT C0.2 and maximum-time controls

650-672
항목한국어 전문 번역
What/sys/devices/system/cpu/umwait_control; /sys/devices/system/cpu/umwait_control/enable_c02; /sys/devices/system/cpu/umwait_control/max_time
Date2019년 5월
ContactLinux kernel mailing list <[email protected]>
DescriptionUMWAIT를 제어합니다. enable_c02는 UMWAIT C0.2 state의 read/write control입니다. Read 결과 0은 C0.2 disabled, 1은 enabled를 뜻합니다. 'y', '1', 'on'을 write하면 C0.2를 enable하고 'n', '0', 'off'를 write하면 disable하며 interface는 case-insensitive입니다. max_time은 CPU가 C0.1 또는 C0.2 state에 머무를 수 있는 UMWAIT maximum time을 TSC-quanta 단위로 제어하는 read/write interface입니다. Time은 unsigned 32-bit number이고 0은 limit가 없음을 뜻하며 low-order 2 bits는 0이어야 합니다.
UMWAIT controls
AttributeValues / constraints
enable_c02 read0 disabled, 1 enabled
enable_c02 writey/1/on or n/0/off, case-insensitive
max_timeUnsigned 32-bit TSC-quanta; 0 means unlimited
max_time alignmentLow-order two bits must be zero

C0.2 enable aliases와 maximum-time constraints입니다.

SEV-SNP guest privilege level

673-684
항목한국어 전문 번역
What/sys/devices/system/cpu/sev; /sys/devices/system/cpu/sev/vmpl
Date2024년 5월
ContactLinux kernel mailing list <[email protected]>
DescriptionSecure Encrypted Virtualization(SEV) 정보입니다. SEV-SNP guest로 실행 중일 때만 이 directory가 존재합니다. vmpl은 SEV-SNP guest가 실행 중인 Virtual Machine Privilege Level(VMPL)을 보고합니다.

POWER secure virtual-machine state

685-694
항목한국어 전문 번역
What/sys/devices/system/cpu/svm
Date2019년 8월
ContactLinux kernel mailing list <[email protected]>; Linux for PowerPC mailing list <[email protected]>
DescriptionSecure Virtual Machine 상태입니다. 값이 1이면 system이 POWER9 이상 processor의 Protected Execution Facility를 사용 중임을 뜻하며, 즉 Secure Virtual Machine입니다.

Processor Utilization Resources Register ticks

695-705
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/purr
Date2005년 4월
ContactLinux for PowerPC mailing list <[email protected]>
DescriptionSystem boot 이후 이 CPU의 PURR ticks를 제공합니다. Processor Utilization Resources Register(PURR)는 CPU thread가 사용한 resource를 추정하는 64-bit counter입니다. Register 내용은 monotonically increase합니다. 이 sysfs interface는 cpuX의 PURR tick 수를 expose합니다.
PowerPC utilization counters
AttributeReported ticks
purrMonotonic processor-utilization estimate since boot
spurrFrequency-invariant utilization estimate since boot
idle_purrPURR ticks accumulated while idle
idle_spurrSPURR ticks accumulated while idle

전체 resource estimate와 idle-only tick views입니다.

Scaled Processor Utilization Resources ticks

706-717
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/spurr
Date2006년 12월
ContactLinux for PowerPC mailing list <[email protected]>
DescriptionSystem boot 이후 이 CPU의 SPURR ticks를 제공합니다. Scaled Processor Utilization Resources Register(SPURR)는 CPU thread가 사용한 resource를 frequency-invariant하게 추정하는 64-bit counter입니다. Register 내용은 monotonically increase합니다. 이 sysfs interface는 cpuX의 SPURR tick 수를 expose합니다.

Idle PURR ticks

718-725
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/idle_purr
Date2020년 4월
ContactLinux for PowerPC mailing list <[email protected]>
DescriptioncpuX가 idle 상태였을 때의 PURR ticks입니다. 이 sysfs interface는 cpuX가 idle일 때 누적한 PURR tick 수를 expose합니다.

Idle SPURR ticks

726-733
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/idle_spurr
Date2020년 4월
ContactLinux for PowerPC mailing list <[email protected]>
DescriptioncpuX가 idle 상태였을 때의 SPURR ticks입니다. 이 sysfs interface는 cpuX가 idle일 때 누적한 SPURR tick 수를 expose합니다.

Preferred ARM MTE tag-checking mode

734-751
항목한국어 전문 번역
What/sys/devices/system/cpu/cpuX/mte_tcf_preferred
Date2021년 7월
ContactLinux ARM Kernel Mailing list <[email protected]>
DescriptionPreferred MTE tag-checking mode입니다. User program이 둘 이상의 MTE tag-checking mode를 지정하면 이 sysfs node가 해당 CPU에 task를 schedule할 때 우선할 mode를 지정합니다. "sync"는 synchronous mode, "asymm"은 asymmetric mode, "async"는 asynchronous mode를 우선합니다. Documentation/arch/arm64/memory-tagging-extension.rst도 참조하십시오.
Preferred MTE tag-checking values
ValuePreferred mode
syncSynchronous
asymmAsymmetric
asyncAsynchronous

원문의 ASCII value table을 구조화했습니다.

Full-dynticks CPU list

752-758
항목한국어 전문 번역
What/sys/devices/system/cpu/nohz_full
Date2015년 4월
ContactLinux kernel mailing list <[email protected]>
Description(RO) nohz_full mode에 있는 CPU 목록입니다. 이 CPU들은 boot parameter "nohz_full="로 설정됩니다.
Boot-configured CPU sets
AttributeBoot parameterEffect
nohz_fullnohz_full=CPUs in full-dynticks mode
isolatedisolcpus=CPUs excluded from load balancing

Tick suppression과 scheduler load-balancing isolation을 구분합니다.

Load-balancing-isolated CPU list

759-766
항목한국어 전문 번역
What/sys/devices/system/cpu/isolated
Date2015년 4월
ContactLinux kernel mailing list <[email protected]>
Description(RO) Isolated되어 load balancing에 참여하지 않는 CPU 목록입니다. 이 CPU들은 boot parameter "isolcpus="로 설정됩니다.

Kexec crash-segment hotplug updating

767-774
항목한국어 전문 번역
What/sys/devices/system/cpu/crash_hotplug
Date2023년 8월
ContactLinux kernel mailing list <[email protected]>
Description(RO) Memory hot-unplug/plug 및 CPU offline/online event에서 kernel이 관련 kexec segment를 update하는지 나타냅니다. 이 기능을 사용하면 kdump kernel을 reload할 필요가 없습니다.
Crash-kernel hotplug update
Memory hotplug or CPU online/offline eventKernel updates relevant kexec segmentsExisting kdump kernel remains usableNo kdump-kernel reload required

지원 kernel은 topology 변화에 맞춰 kexec segment를 갱신합니다.

CPUs eligible to be brought online

775-779
항목한국어 전문 번역
What/sys/devices/system/cpu/enabled
Date2022년 11월
ContactLinux kernel mailing list <[email protected]>
Description(RO) Online으로 전환할 수 있는 CPU 목록입니다.