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04dab58a39
Add two new metrics for CPU idle states, "above" and "below", to count the number of times the given state had been asked for (or entered from the kernel's perspective), but the observed idle duration turned out to be too short or too long for it (respectively). These metrics help to estimate the quality of the CPU idle governor in use. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
521 lines
20 KiB
Plaintext
521 lines
20 KiB
Plaintext
What: /sys/devices/system/cpu/
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Date: pre-git history
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description:
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A collection of both global and individual CPU attributes
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Individual CPU attributes are contained in subdirectories
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named by the kernel's logical CPU number, e.g.:
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/sys/devices/system/cpu/cpu#/
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What: /sys/devices/system/cpu/kernel_max
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/sys/devices/system/cpu/offline
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/sys/devices/system/cpu/online
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/sys/devices/system/cpu/possible
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/sys/devices/system/cpu/present
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Date: December 2008
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: CPU topology files that describe kernel limits related to
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hotplug. Briefly:
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kernel_max: the maximum cpu index allowed by the kernel
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configuration.
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offline: cpus that are not online because they have been
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HOTPLUGGED off or exceed the limit of cpus allowed by the
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kernel configuration (kernel_max above).
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online: cpus that are online and being scheduled.
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possible: cpus that have been allocated resources and can be
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brought online if they are present.
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present: cpus that have been identified as being present in
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the system.
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See Documentation/cputopology.txt for more information.
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What: /sys/devices/system/cpu/probe
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/sys/devices/system/cpu/release
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Date: November 2009
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Dynamic addition and removal of CPU's. This is not hotplug
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removal, this is meant complete removal/addition of the CPU
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from the system.
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probe: writes to this file will dynamically add a CPU to the
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system. Information written to the file to add CPU's is
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architecture specific.
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release: writes to this file dynamically remove a CPU from
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the system. Information writtento the file to remove CPU's
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is architecture specific.
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What: /sys/devices/system/cpu/cpu#/node
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Date: October 2009
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Contact: Linux memory management mailing list <linux-mm@kvack.org>
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Description: Discover NUMA node a CPU belongs to
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When CONFIG_NUMA is enabled, a symbolic link that points
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to the corresponding NUMA node directory.
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For example, the following symlink is created for cpu42
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in NUMA node 2:
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/sys/devices/system/cpu/cpu42/node2 -> ../../node/node2
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What: /sys/devices/system/cpu/cpu#/topology/core_id
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/sys/devices/system/cpu/cpu#/topology/core_siblings
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/sys/devices/system/cpu/cpu#/topology/core_siblings_list
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/sys/devices/system/cpu/cpu#/topology/physical_package_id
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/sys/devices/system/cpu/cpu#/topology/thread_siblings
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/sys/devices/system/cpu/cpu#/topology/thread_siblings_list
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Date: December 2008
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: CPU topology files that describe a logical CPU's relationship
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to other cores and threads in the same physical package.
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One cpu# directory is created per logical CPU in the system,
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e.g. /sys/devices/system/cpu/cpu42/.
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Briefly, the files above are:
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core_id: the CPU core ID of cpu#. Typically it is the
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hardware platform's identifier (rather than the kernel's).
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The actual value is architecture and platform dependent.
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core_siblings: internal kernel map of cpu#'s hardware threads
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within the same physical_package_id.
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core_siblings_list: human-readable list of the logical CPU
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numbers within the same physical_package_id as cpu#.
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physical_package_id: physical package id of cpu#. Typically
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corresponds to a physical socket number, but the actual value
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is architecture and platform dependent.
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thread_siblings: internel kernel map of cpu#'s hardware
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threads within the same core as cpu#
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thread_siblings_list: human-readable list of cpu#'s hardware
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threads within the same core as cpu#
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See Documentation/cputopology.txt for more information.
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What: /sys/devices/system/cpu/cpuidle/current_driver
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/sys/devices/system/cpu/cpuidle/current_governer_ro
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/sys/devices/system/cpu/cpuidle/available_governors
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/sys/devices/system/cpu/cpuidle/current_governor
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Date: September 2007
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Discover cpuidle policy and mechanism
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Various CPUs today support multiple idle levels that are
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differentiated by varying exit latencies and power
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consumption during idle.
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Idle policy (governor) is differentiated from idle mechanism
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(driver)
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current_driver: (RO) displays current idle mechanism
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current_governor_ro: (RO) displays current idle policy
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With the cpuidle_sysfs_switch boot option enabled (meant for
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developer testing), the following three attributes are visible
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instead:
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current_driver: same as described above
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available_governors: (RO) displays a space separated list of
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available governors
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current_governor: (RW) displays current idle policy. Users can
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switch the governor at runtime by writing to this file.
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See files in Documentation/cpuidle/ for more information.
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/name
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/latency
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/power
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/time
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/usage
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/above
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/sys/devices/system/cpu/cpuX/cpuidle/stateN/below
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Date: September 2007
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KernelVersion: v2.6.24
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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The directory /sys/devices/system/cpu/cpuX/cpuidle contains per
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logical CPU specific cpuidle information for each online cpu X.
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The processor idle states which are available for use have the
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following attributes:
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name: (RO) Name of the idle state (string).
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latency: (RO) The latency to exit out of this idle state (in
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microseconds).
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power: (RO) The power consumed while in this idle state (in
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milliwatts).
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time: (RO) The total time spent in this idle state (in microseconds).
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usage: (RO) Number of times this state was entered (a count).
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above: (RO) Number of times this state was entered, but the
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observed CPU idle duration was too short for it (a count).
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below: (RO) Number of times this state was entered, but the
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observed CPU idle duration was too long for it (a count).
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/desc
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Date: February 2008
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KernelVersion: v2.6.25
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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(RO) A small description about the idle state (string).
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/disable
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Date: March 2012
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KernelVersion: v3.10
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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(RW) Option to disable this idle state (bool). The behavior and
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the effect of the disable variable depends on the implementation
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of a particular governor. In the ladder governor, for example,
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it is not coherent, i.e. if one is disabling a light state, then
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all deeper states are disabled as well, but the disable variable
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does not reflect it. Likewise, if one enables a deep state but a
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lighter state still is disabled, then this has no effect.
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/residency
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Date: March 2014
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KernelVersion: v3.15
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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(RO) Display the target residency i.e. the minimum amount of
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time (in microseconds) this cpu should spend in this idle state
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to make the transition worth the effort.
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/
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Date: March 2018
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KernelVersion: v4.17
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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Idle state usage statistics related to suspend-to-idle.
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This attribute group is only present for states that can be
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used in suspend-to-idle with suspended timekeeping.
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/time
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Date: March 2018
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KernelVersion: v4.17
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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Total time spent by the CPU in suspend-to-idle (with scheduler
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tick suspended) after requesting this state.
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What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/s2idle/usage
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Date: March 2018
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KernelVersion: v4.17
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Contact: Linux power management list <linux-pm@vger.kernel.org>
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Description:
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Total number of times this state has been requested by the CPU
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while entering suspend-to-idle.
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What: /sys/devices/system/cpu/cpu#/cpufreq/*
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Date: pre-git history
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Contact: linux-pm@vger.kernel.org
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Description: Discover and change clock speed of CPUs
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Clock scaling allows you to change the clock speed of the
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CPUs on the fly. This is a nice method to save battery
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power, because the lower the clock speed, the less power
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the CPU consumes.
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There are many knobs to tweak in this directory.
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See files in Documentation/cpu-freq/ for more information.
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What: /sys/devices/system/cpu/cpu#/cpufreq/freqdomain_cpus
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Date: June 2013
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Contact: linux-pm@vger.kernel.org
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Description: Discover CPUs in the same CPU frequency coordination domain
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freqdomain_cpus is the list of CPUs (online+offline) that share
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the same clock/freq domain (possibly at the hardware level).
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That information may be hidden from the cpufreq core and the
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value of related_cpus may be different from freqdomain_cpus. This
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attribute is useful for user space DVFS controllers to get better
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power/performance results for platforms using acpi-cpufreq.
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This file is only present if the acpi-cpufreq driver is in use.
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What: /sys/devices/system/cpu/cpu*/cache/index3/cache_disable_{0,1}
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Date: August 2008
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KernelVersion: 2.6.27
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Disable L3 cache indices
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These files exist in every CPU's cache/index3 directory. Each
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cache_disable_{0,1} file corresponds to one disable slot which
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can be used to disable a cache index. Reading from these files
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on a processor with this functionality will return the currently
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disabled index for that node. There is one L3 structure per
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node, or per internal node on MCM machines. Writing a valid
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index to one of these files will cause the specificed cache
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index to be disabled.
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All AMD processors with L3 caches provide this functionality.
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For details, see BKDGs at
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http://developer.amd.com/documentation/guides/Pages/default.aspx
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What: /sys/devices/system/cpu/cpufreq/boost
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Date: August 2012
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Processor frequency boosting control
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This switch controls the boost setting for the whole system.
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Boosting allows the CPU and the firmware to run at a frequency
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beyound it's nominal limit.
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More details can be found in
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Documentation/admin-guide/pm/cpufreq.rst
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What: /sys/devices/system/cpu/cpu#/crash_notes
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/sys/devices/system/cpu/cpu#/crash_notes_size
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Date: April 2013
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Contact: kexec@lists.infradead.org
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Description: address and size of the percpu note.
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crash_notes: the physical address of the memory that holds the
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note of cpu#.
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crash_notes_size: size of the note of cpu#.
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What: /sys/devices/system/cpu/intel_pstate/max_perf_pct
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/sys/devices/system/cpu/intel_pstate/min_perf_pct
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/sys/devices/system/cpu/intel_pstate/no_turbo
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Date: February 2013
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Contact: linux-pm@vger.kernel.org
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Description: Parameters for the Intel P-state driver
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Logic for selecting the current P-state in Intel
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Sandybridge+ processors. The three knobs control
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limits for the P-state that will be requested by the
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driver.
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max_perf_pct: limits the maximum P state that will be requested by
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the driver stated as a percentage of the available performance.
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min_perf_pct: limits the minimum P state that will be requested by
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the driver stated as a percentage of the available performance.
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no_turbo: limits the driver to selecting P states below the turbo
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frequency range.
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More details can be found in
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Documentation/admin-guide/pm/intel_pstate.rst
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What: /sys/devices/system/cpu/cpu*/cache/index*/<set_of_attributes_mentioned_below>
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Date: July 2014(documented, existed before August 2008)
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Contact: Sudeep Holla <sudeep.holla@arm.com>
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Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Parameters for the CPU cache attributes
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allocation_policy:
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- WriteAllocate: allocate a memory location to a cache line
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on a cache miss because of a write
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- ReadAllocate: allocate a memory location to a cache line
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on a cache miss because of a read
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- ReadWriteAllocate: both writeallocate and readallocate
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attributes: LEGACY used only on IA64 and is same as write_policy
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coherency_line_size: the minimum amount of data in bytes that gets
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transferred from memory to cache
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level: the cache hierarchy in the multi-level cache configuration
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number_of_sets: total number of sets in the cache, a set is a
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collection of cache lines with the same cache index
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physical_line_partition: number of physical cache line per cache tag
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shared_cpu_list: the list of logical cpus sharing the cache
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shared_cpu_map: logical cpu mask containing the list of cpus sharing
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the cache
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size: the total cache size in kB
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type:
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- Instruction: cache that only holds instructions
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- Data: cache that only caches data
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- Unified: cache that holds both data and instructions
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ways_of_associativity: degree of freedom in placing a particular block
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of memory in the cache
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write_policy:
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- WriteThrough: data is written to both the cache line
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and to the block in the lower-level memory
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- WriteBack: data is written only to the cache line and
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the modified cache line is written to main
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memory only when it is replaced
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What: /sys/devices/system/cpu/cpu*/cache/index*/id
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Date: September 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Cache id
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The id provides a unique number for a specific instance of
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a cache of a particular type. E.g. there may be a level
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3 unified cache on each socket in a server and we may
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assign them ids 0, 1, 2, ...
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Note that id value can be non-contiguous. E.g. level 1
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caches typically exist per core, but there may not be a
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power of two cores on a socket, so these caches may be
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numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...
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What: /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/turbo_stat
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/sub_turbo_stat
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/unthrottle
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/powercap
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overtemp
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/supply_fault
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/overcurrent
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/sys/devices/system/cpu/cpuX/cpufreq/throttle_stats/occ_reset
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Date: March 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
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Description: POWERNV CPUFreq driver's frequency throttle stats directory and
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attributes
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'cpuX/cpufreq/throttle_stats' directory contains the CPU frequency
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throttle stat attributes for the chip. The throttle stats of a cpu
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is common across all the cpus belonging to a chip. Below are the
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throttle attributes exported in the 'throttle_stats' directory:
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- turbo_stat : This file gives the total number of times the max
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frequency is throttled to lower frequency in turbo (at and above
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nominal frequency) range of frequencies.
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- sub_turbo_stat : This file gives the total number of times the
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max frequency is throttled to lower frequency in sub-turbo(below
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nominal frequency) range of frequencies.
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- unthrottle : This file gives the total number of times the max
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frequency is unthrottled after being throttled.
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- powercap : This file gives the total number of times the max
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frequency is throttled due to 'Power Capping'.
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- overtemp : This file gives the total number of times the max
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frequency is throttled due to 'CPU Over Temperature'.
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- supply_fault : This file gives the total number of times the
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max frequency is throttled due to 'Power Supply Failure'.
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- overcurrent : This file gives the total number of times the
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max frequency is throttled due to 'Overcurrent'.
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- occ_reset : This file gives the total number of times the max
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frequency is throttled due to 'OCC Reset'.
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The sysfs attributes representing different throttle reasons like
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powercap, overtemp, supply_fault, overcurrent and occ_reset map to
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the reasons provided by OCC firmware for throttling the frequency.
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What: /sys/devices/system/cpu/cpufreq/policyX/throttle_stats
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/turbo_stat
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/sub_turbo_stat
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/unthrottle
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/powercap
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overtemp
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/supply_fault
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/overcurrent
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/sys/devices/system/cpu/cpufreq/policyX/throttle_stats/occ_reset
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Date: March 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Linux for PowerPC mailing list <linuxppc-dev@ozlabs.org>
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Description: POWERNV CPUFreq driver's frequency throttle stats directory and
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attributes
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'policyX/throttle_stats' directory and all the attributes are same as
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the /sys/devices/system/cpu/cpuX/cpufreq/throttle_stats directory and
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attributes which give the frequency throttle information of the chip.
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What: /sys/devices/system/cpu/cpuX/regs/
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/sys/devices/system/cpu/cpuX/regs/identification/
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/sys/devices/system/cpu/cpuX/regs/identification/midr_el1
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/sys/devices/system/cpu/cpuX/regs/identification/revidr_el1
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Date: June 2016
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Contact: Linux ARM Kernel Mailing list <linux-arm-kernel@lists.infradead.org>
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Description: AArch64 CPU registers
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'identification' directory exposes the CPU ID registers for
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identifying model and revision of the CPU.
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What: /sys/devices/system/cpu/cpu#/cpu_capacity
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Date: December 2016
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: information about CPUs heterogeneity.
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cpu_capacity: capacity of cpu#.
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What: /sys/devices/system/cpu/vulnerabilities
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/sys/devices/system/cpu/vulnerabilities/meltdown
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/sys/devices/system/cpu/vulnerabilities/spectre_v1
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/sys/devices/system/cpu/vulnerabilities/spectre_v2
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/sys/devices/system/cpu/vulnerabilities/spec_store_bypass
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/sys/devices/system/cpu/vulnerabilities/l1tf
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Date: January 2018
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Information about CPU vulnerabilities
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|
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The files are named after the code names of CPU
|
|
vulnerabilities. The output of those files reflects the
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state of the CPUs in the system. Possible output values:
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|
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"Not affected" CPU is not affected by the vulnerability
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"Vulnerable" CPU is affected and no mitigation in effect
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"Mitigation: $M" CPU is affected and mitigation $M is in effect
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|
|
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Details about the l1tf file can be found in
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|
Documentation/admin-guide/l1tf.rst
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What: /sys/devices/system/cpu/smt
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/sys/devices/system/cpu/smt/active
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/sys/devices/system/cpu/smt/control
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Date: June 2018
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Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
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Description: Control Symetric Multi Threading (SMT)
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active: Tells whether SMT is active (enabled and siblings online)
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control: Read/write interface to control SMT. Possible
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values:
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"on" SMT is enabled
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|
"off" SMT is disabled
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"forceoff" SMT is force disabled. Cannot be changed.
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"notsupported" SMT is not supported by the CPU
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If control status is "forceoff" or "notsupported" writes
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are rejected.
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