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/sys/devices/system/cpu/cpu#/cpu_capacity describe information about CPUs heterogeneity (ref. to Documentation/devicetree/bindings/arm/ cpu-capacity.txt). Add such description. Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
376 lines
14 KiB
Plaintext
376 lines
14 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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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: displays current idle mechanism
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current_governor_ro: displays current idle policy
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See files in Documentation/cpuidle/ for more information.
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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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In particular, read Documentation/cpu-freq/user-guide.txt
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to learn how to control the knobs.
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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 Documentation/cpu-freq/boost.txt
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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 Documentation/cpu-freq/intel-pstate.txt
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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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