1 What: /sys/devices/system/cpu/
3 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
5 A collection of both global and individual CPU attributes
7 Individual CPU attributes are contained in subdirectories
8 named by the kernel's logical CPU number, e.g.:
10 /sys/devices/system/cpu/cpuX/
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
18 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
19 Description: CPU topology files that describe kernel limits related to
22 kernel_max: the maximum cpu index allowed by the kernel
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).
29 online: cpus that are online and being scheduled.
31 possible: cpus that have been allocated resources and can be
32 brought online if they are present.
34 present: cpus that have been identified as being present in
37 See Documentation/admin-guide/cputopology.rst for more information.
40 What: /sys/devices/system/cpu/probe
41 /sys/devices/system/cpu/release
43 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
44 Description: Dynamic addition and removal of CPU's. This is not hotplug
45 removal, this is meant complete removal/addition of the CPU
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.
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.
56 What: /sys/devices/system/cpu/cpuX/node
58 Contact: Linux memory management mailing list <linux-mm@kvack.org>
59 Description: Discover NUMA node a CPU belongs to
61 When CONFIG_NUMA is enabled, a symbolic link that points
62 to the corresponding NUMA node directory.
64 For example, the following symlink is created for cpu42
67 /sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
70 What: /sys/devices/system/cpu/cpuX/topology/core_id
71 /sys/devices/system/cpu/cpuX/topology/core_siblings
72 /sys/devices/system/cpu/cpuX/topology/core_siblings_list
73 /sys/devices/system/cpu/cpuX/topology/physical_package_id
74 /sys/devices/system/cpu/cpuX/topology/thread_siblings
75 /sys/devices/system/cpu/cpuX/topology/thread_siblings_list
76 /sys/devices/system/cpu/cpuX/topology/ppin
78 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
79 Description: CPU topology files that describe a logical CPU's relationship
80 to other cores and threads in the same physical package.
82 One cpuX directory is created per logical CPU in the system,
83 e.g. /sys/devices/system/cpu/cpu42/.
85 Briefly, the files above are:
87 core_id: the CPU core ID of cpuX. Typically it is the
88 hardware platform's identifier (rather than the kernel's).
89 The actual value is architecture and platform dependent.
91 core_siblings: internal kernel map of cpuX's hardware threads
92 within the same physical_package_id.
94 core_siblings_list: human-readable list of the logical CPU
95 numbers within the same physical_package_id as cpuX.
97 physical_package_id: physical package id of cpuX. Typically
98 corresponds to a physical socket number, but the actual value
99 is architecture and platform dependent.
101 thread_siblings: internal kernel map of cpuX's hardware
102 threads within the same core as cpuX
104 thread_siblings_list: human-readable list of cpuX's hardware
105 threads within the same core as cpuX
107 ppin: human-readable Protected Processor Identification
108 Number of the socket the cpu# belongs to. There should be
109 one per physical_package_id. File is readable only to
112 See Documentation/admin-guide/cputopology.rst for more information.
115 What: /sys/devices/system/cpu/cpuidle/available_governors
116 /sys/devices/system/cpu/cpuidle/current_driver
117 /sys/devices/system/cpu/cpuidle/current_governor
118 /sys/devices/system/cpu/cpuidle/current_governer_ro
120 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
121 Description: Discover cpuidle policy and mechanism
123 Various CPUs today support multiple idle levels that are
124 differentiated by varying exit latencies and power
125 consumption during idle.
127 Idle policy (governor) is differentiated from idle mechanism
130 available_governors: (RO) displays a space separated list of
133 current_driver: (RO) displays current idle mechanism.
135 current_governor: (RW) displays current idle policy. Users can
136 switch the governor at runtime by writing to this file.
138 current_governor_ro: (RO) displays current idle policy.
140 See Documentation/admin-guide/pm/cpuidle.rst and
141 Documentation/driver-api/pm/cpuidle.rst for more information.
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
152 KernelVersion: v2.6.24
153 Contact: Linux power management list <linux-pm@vger.kernel.org>
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:
160 ======== ==== =================================================
161 name: (RO) Name of the idle state (string).
163 latency: (RO) The latency to exit out of this idle state (in
166 power: (RO) The power consumed while in this idle state (in
169 time: (RO) The total time spent in this idle state
172 usage: (RO) Number of times this state was entered (a count).
174 above: (RO) Number of times this state was entered, but the
175 observed CPU idle duration was too short for it
178 below: (RO) Number of times this state was entered, but the
179 observed CPU idle duration was too long for it
181 ======== ==== =================================================
183 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/desc
185 KernelVersion: v2.6.25
186 Contact: Linux power management list <linux-pm@vger.kernel.org>
188 (RO) A small description about the idle state (string).
191 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/disable
194 Contact: Linux power management list <linux-pm@vger.kernel.org>
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.
204 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/default_status
207 Contact: Linux power management list <linux-pm@vger.kernel.org>
209 (RO) The default status of this state, "enabled" or "disabled".
211 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/residency
214 Contact: Linux power management list <linux-pm@vger.kernel.org>
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.
220 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/
223 Contact: Linux power management list <linux-pm@vger.kernel.org>
225 Idle state usage statistics related to suspend-to-idle.
227 This attribute group is only present for states that can be
228 used in suspend-to-idle with suspended timekeeping.
230 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/time
233 Contact: Linux power management list <linux-pm@vger.kernel.org>
235 Total time spent by the CPU in suspend-to-idle (with scheduler
236 tick suspended) after requesting this state.
238 What: /sys/devices/system/cpu/cpuX/cpuidle/state<N>/s2idle/usage
241 Contact: Linux power management list <linux-pm@vger.kernel.org>
243 Total number of times this state has been requested by the CPU
244 while entering suspend-to-idle.
246 What: /sys/devices/system/cpu/cpuX/cpufreq/*
247 Date: pre-git history
248 Contact: linux-pm@vger.kernel.org
249 Description: Discover and change clock speed of CPUs
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
256 There are many knobs to tweak in this directory.
258 See files in Documentation/cpu-freq/ for more information.
261 What: /sys/devices/system/cpu/cpuX/cpufreq/freqdomain_cpus
263 Contact: linux-pm@vger.kernel.org
264 Description: Discover CPUs in the same CPU frequency coordination domain
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.
273 This file is only present if the acpi-cpufreq or the cppc-cpufreq
277 What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
279 KernelVersion: 2.6.27
280 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
281 Description: Disable L3 cache indices
283 These files exist in every CPU's cache/index3 directory. Each
284 cache_disable_{0,1} file corresponds to one disable slot which
285 can be used to disable a cache index. Reading from these files
286 on a processor with this functionality will return the currently
287 disabled index for that node. There is one L3 structure per
288 node, or per internal node on MCM machines. Writing a valid
289 index to one of these files will cause the specified cache
290 index to be disabled.
292 All AMD processors with L3 caches provide this functionality.
293 For details, see BKDGs at
294 https://www.amd.com/en/support/tech-docs?keyword=bios+kernel
297 What: /sys/devices/system/cpu/cpufreq/boost
299 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
300 Description: Processor frequency boosting control
302 This switch controls the boost setting for the whole system.
303 Boosting allows the CPU and the firmware to run at a frequency
304 beyond it's nominal limit.
306 More details can be found in
307 Documentation/admin-guide/pm/cpufreq.rst
310 What: /sys/devices/system/cpu/cpuX/crash_notes
311 /sys/devices/system/cpu/cpuX/crash_notes_size
313 Contact: kexec@lists.infradead.org
314 Description: address and size of the percpu note.
316 crash_notes: the physical address of the memory that holds the
319 crash_notes_size: size of the note of cpuX.
322 What: /sys/devices/system/cpu/intel_pstate/max_perf_pct
323 /sys/devices/system/cpu/intel_pstate/min_perf_pct
324 /sys/devices/system/cpu/intel_pstate/no_turbo
326 Contact: linux-pm@vger.kernel.org
327 Description: Parameters for the Intel P-state driver
329 Logic for selecting the current P-state in Intel
330 Sandybridge+ processors. The three knobs control
331 limits for the P-state that will be requested by the
334 max_perf_pct: limits the maximum P state that will be requested by
335 the driver stated as a percentage of the available performance.
337 min_perf_pct: limits the minimum P state that will be requested by
338 the driver stated as a percentage of the available performance.
340 no_turbo: limits the driver to selecting P states below the turbo
343 More details can be found in
344 Documentation/admin-guide/pm/intel_pstate.rst
346 What: /sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
347 Date: July 2014(documented, existed before August 2008)
348 Contact: Sudeep Holla <sudeep.holla@arm.com>
349 Linux kernel mailing list <linux-kernel@vger.kernel.org>
350 Description: Parameters for the CPU cache attributes
354 allocate a memory location to a cache line
355 on a cache miss because of a write
357 allocate a memory location to a cache line
358 on a cache miss because of a read
360 both writeallocate and readallocate
363 LEGACY used only on IA64 and is same as write_policy
366 the minimum amount of data in bytes that gets
367 transferred from memory to cache
370 the cache hierarchy in the multi-level cache configuration
373 total number of sets in the cache, a set is a
374 collection of cache lines with the same cache index
376 physical_line_partition:
377 number of physical cache line per cache tag
380 the list of logical cpus sharing the cache
383 logical cpu mask containing the list of cpus sharing
387 the total cache size in kB
390 - Instruction: cache that only holds instructions
391 - Data: cache that only caches data
392 - Unified: cache that holds both data and instructions
394 ways_of_associativity:
395 degree of freedom in placing a particular block
396 of memory in the cache
400 data is written to both the cache line
401 and to the block in the lower-level memory
403 data is written only to the cache line and
404 the modified cache line is written to main
405 memory only when it is replaced
408 What: /sys/devices/system/cpu/cpu*/cache/index*/id
410 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
411 Description: Cache id
413 The id provides a unique number for a specific instance of
414 a cache of a particular type. E.g. there may be a level
415 3 unified cache on each socket in a server and we may
416 assign them ids 0, 1, 2, ...
418 Note that id value can be non-contiguous. E.g. level 1
419 caches typically exist per core, but there may not be a
420 power of two cores on a socket, so these caches may be
421 numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...
423 What: /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats
424 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
425 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat
426 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
427 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
428 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
429 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
430 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
431 /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
433 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
434 Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
435 Description: POWERNV CPUFreq driver's frequency throttle stats directory and
438 'cpuX/cpufreq/throttle_stats' directory contains the CPU frequency
439 throttle stat attributes for the chip. The throttle stats of a cpu
440 is common across all the cpus belonging to a chip. Below are the
441 throttle attributes exported in the 'throttle_stats' directory:
443 - turbo_stat : This file gives the total number of times the max
444 frequency is throttled to lower frequency in turbo (at and above
445 nominal frequency) range of frequencies.
447 - sub_turbo_stat : This file gives the total number of times the
448 max frequency is throttled to lower frequency in sub-turbo(below
449 nominal frequency) range of frequencies.
451 - unthrottle : This file gives the total number of times the max
452 frequency is unthrottled after being throttled.
454 - powercap : This file gives the total number of times the max
455 frequency is throttled due to 'Power Capping'.
457 - overtemp : This file gives the total number of times the max
458 frequency is throttled due to 'CPU Over Temperature'.
460 - supply_fault : This file gives the total number of times the
461 max frequency is throttled due to 'Power Supply Failure'.
463 - overcurrent : This file gives the total number of times the
464 max frequency is throttled due to 'Overcurrent'.
466 - occ_reset : This file gives the total number of times the max
467 frequency is throttled due to 'OCC Reset'.
469 The sysfs attributes representing different throttle reasons like
470 powercap, overtemp, supply_fault, overcurrent and occ_reset map to
471 the reasons provided by OCC firmware for throttling the frequency.
473 What: /sys/devices/system/cpu/cpufreq/policyX/throttle_stats
474 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat
475 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat
476 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle
477 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap
478 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp
479 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault
480 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent
481 /sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
483 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
484 Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
485 Description: POWERNV CPUFreq driver's frequency throttle stats directory and
488 'policyX/throttle_stats' directory and all the attributes are same as
489 the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
490 attributes which give the frequency throttle information of the chip.
492 What: /sys/devices/system/cpu/cpuX/regs/
493 /sys/devices/system/cpu/cpuX/regs/identification/
494 /sys/devices/system/cpu/cpuX/regs/identification/midr_el1
495 /sys/devices/system/cpu/cpuX/regs/identification/revidr_el1
496 /sys/devices/system/cpu/cpuX/regs/identification/smidr_el1
498 Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
499 Description: AArch64 CPU registers
501 'identification' directory exposes the CPU ID registers for
502 identifying model and revision of the CPU and SMCU.
504 What: /sys/devices/system/cpu/aarch32_el0
506 Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
507 Description: Identifies the subset of CPUs in the system that can execute
508 AArch32 (32-bit ARM) applications. If present, the same format as
509 /sys/devices/system/cpu/{offline,online,possible,present} is used.
510 If absent, then all or none of the CPUs can execute AArch32
511 applications and execve() will behave accordingly.
513 What: /sys/devices/system/cpu/cpuX/cpu_capacity
515 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
516 Description: information about CPUs heterogeneity.
518 cpu_capacity: capacity of cpuX.
520 What: /sys/devices/system/cpu/vulnerabilities
521 /sys/devices/system/cpu/vulnerabilities/meltdown
522 /sys/devices/system/cpu/vulnerabilities/spectre_v1
523 /sys/devices/system/cpu/vulnerabilities/spectre_v2
524 /sys/devices/system/cpu/vulnerabilities/spec_store_bypass
525 /sys/devices/system/cpu/vulnerabilities/l1tf
526 /sys/devices/system/cpu/vulnerabilities/mds
527 /sys/devices/system/cpu/vulnerabilities/srbds
528 /sys/devices/system/cpu/vulnerabilities/tsx_async_abort
529 /sys/devices/system/cpu/vulnerabilities/itlb_multihit
530 /sys/devices/system/cpu/vulnerabilities/mmio_stale_data
532 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
533 Description: Information about CPU vulnerabilities
535 The files are named after the code names of CPU
536 vulnerabilities. The output of those files reflects the
537 state of the CPUs in the system. Possible output values:
539 ================ ==============================================
540 "Not affected" CPU is not affected by the vulnerability
541 "Vulnerable" CPU is affected and no mitigation in effect
542 "Mitigation: $M" CPU is affected and mitigation $M is in effect
543 ================ ==============================================
545 See also: Documentation/admin-guide/hw-vuln/index.rst
547 What: /sys/devices/system/cpu/smt
548 /sys/devices/system/cpu/smt/active
549 /sys/devices/system/cpu/smt/control
551 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
552 Description: Control Symmetric Multi Threading (SMT)
554 active: Tells whether SMT is active (enabled and siblings online)
556 control: Read/write interface to control SMT. Possible
559 ================ =========================================
561 "off" SMT is disabled
562 "forceoff" SMT is force disabled. Cannot be changed.
563 "notsupported" SMT is not supported by the CPU
564 "notimplemented" SMT runtime toggling is not
565 implemented for the architecture
566 ================ =========================================
568 If control status is "forceoff" or "notsupported" writes
571 What: /sys/devices/system/cpu/cpuX/power/energy_perf_bias
573 Contact: linux-pm@vger.kernel.org
574 Description: Intel Energy and Performance Bias Hint (EPB)
576 EPB for the given CPU in a sliding scale 0 - 15, where a value
577 of 0 corresponds to a hint preference for highest performance
578 and a value of 15 corresponds to the maximum energy savings.
580 In order to change the EPB value for the CPU, write either
581 a number in the 0 - 15 sliding scale above, or one of the
582 strings: "performance", "balance-performance", "normal",
583 "balance-power", "power" (that represent values reflected by
584 their meaning), to this attribute.
586 This attribute is present for all online CPUs supporting the
589 What: /sys/devices/system/cpu/umwait_control
590 /sys/devices/system/cpu/umwait_control/enable_c02
591 /sys/devices/system/cpu/umwait_control/max_time
593 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
594 Description: Umwait control
596 enable_c02: Read/write interface to control umwait C0.2 state
597 Read returns C0.2 state status:
601 Write 'y' or '1' or 'on' to enable C0.2 state.
602 Write 'n' or '0' or 'off' to disable C0.2 state.
604 The interface is case insensitive.
606 max_time: Read/write interface to control umwait maximum time
607 in TSC-quanta that the CPU can reside in either C0.1
608 or C0.2 state. The time is an unsigned 32-bit number.
609 Note that a value of zero means there is no limit.
610 Low order two bits must be zero.
612 What: /sys/devices/system/cpu/svm
614 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
615 Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
616 Description: Secure Virtual Machine
618 If 1, it means the system is using the Protected Execution
619 Facility in POWER9 and newer processors. i.e., it is a Secure
622 What: /sys/devices/system/cpu/cpuX/purr
624 Contact: Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
625 Description: PURR ticks for this CPU since the system boot.
627 The Processor Utilization Resources Register (PURR) is
628 a 64-bit counter which provides an estimate of the
629 resources used by the CPU thread. The contents of this
630 register increases monotonically. This sysfs interface
631 exposes the number of PURR ticks for cpuX.
633 What: /sys/devices/system/cpu/cpuX/spurr
635 Contact: Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
636 Description: SPURR ticks for this CPU since the system boot.
638 The Scaled Processor Utilization Resources Register
639 (SPURR) is a 64-bit counter that provides a frequency
640 invariant estimate of the resources used by the CPU
641 thread. The contents of this register increases
642 monotonically. This sysfs interface exposes the number
643 of SPURR ticks for cpuX.
645 What: /sys/devices/system/cpu/cpuX/idle_purr
647 Contact: Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
648 Description: PURR ticks for cpuX when it was idle.
650 This sysfs interface exposes the number of PURR ticks
651 for cpuX when it was idle.
653 What: /sys/devices/system/cpu/cpuX/idle_spurr
655 Contact: Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
656 Description: SPURR ticks for cpuX when it was idle.
658 This sysfs interface exposes the number of SPURR ticks
659 for cpuX when it was idle.
661 What: /sys/devices/system/cpu/cpuX/mte_tcf_preferred
663 Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
664 Description: Preferred MTE tag checking mode
666 When a user program specifies more than one MTE tag checking
667 mode, this sysfs node is used to specify which mode should
668 be preferred when scheduling a task on that CPU. Possible
671 ================ ==============================================
672 "sync" Prefer synchronous mode
673 "asymm" Prefer asymmetric mode
674 "async" Prefer asynchronous mode
675 ================ ==============================================
677 See also: Documentation/arm64/memory-tagging-extension.rst
679 What: /sys/devices/system/cpu/nohz_full
681 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
683 (RO) the list of CPUs that are in nohz_full mode.
684 These CPUs are set by boot parameter "nohz_full=".
686 What: /sys/devices/system/cpu/isolated
688 Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
690 (RO) the list of CPUs that are isolated and don't
691 participate in load balancing. These CPUs are set by
692 boot parameter "isolcpus=".