Documentation: ABI: /sys/devices/system/cpu/cpu#/ topology files (663fb2fc) · Commits · e / devices / android_kernel_oneplus_sm8150

Documentation/ABI/testing/sysfs-devices-system-cpu

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	@@ -38,6 +38,45 @@ Description: CPU topology files that describe kernel limits related to
	See Documentation/cputopology.txt for more information.		See Documentation/cputopology.txt for more information.


			What: /sys/devices/system/cpu/cpu#/topology/core_id
			/sys/devices/system/cpu/cpu#/topology/core_siblings
			/sys/devices/system/cpu/cpu#/topology/core_siblings_list
			/sys/devices/system/cpu/cpu#/topology/physical_package_id
			/sys/devices/system/cpu/cpu#/topology/thread_siblings
			/sys/devices/system/cpu/cpu#/topology/thread_siblings_list
			Date: December 2008
			Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org>
			Description: CPU topology files that describe a logical CPU's relationship
			to other cores and threads in the same physical package.

			One cpu# directory is created per logical CPU in the system,
			e.g. /sys/devices/system/cpu/cpu42/.

			Briefly, the files above are:

			core_id: the CPU core ID of cpu#. Typically it is the
			hardware platform's identifier (rather than the kernel's).
			The actual value is architecture and platform dependent.

			core_siblings: internal kernel map of cpu#'s hardware threads
			within the same physical_package_id.

			core_siblings_list: human-readable list of the logical CPU
			numbers within the same physical_package_id as cpu#.

			physical_package_id: physical package id of cpu#. Typically
			corresponds to a physical socket number, but the actual value
			is architecture and platform dependent.

			thread_siblings: internel kernel map of cpu#'s hardware
			threads within the same core as cpu#

			thread_siblings_list: human-readable list of cpu#'s hardware
			threads within the same core as cpu#

			See Documentation/cputopology.txt for more information.


	What: /sys/devices/system/cpu/cpu/cache/index/cache_disable_X		What: /sys/devices/system/cpu/cpu/cache/index/cache_disable_X
	Date: August 2008		Date: August 2008
	KernelVersion: 2.6.27		KernelVersion: 2.6.27

Documentation/cputopology.txt

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	Export cpu topology info via sysfs. Items (attributes) are similar		Export CPU topology info via sysfs. Items (attributes) are similar
	to /proc/cpuinfo.		to /proc/cpuinfo.

	1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:		1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
	represent the physical package id of cpu X;
			physical package id of cpuX. Typically corresponds to a physical
			socket number, but the actual value is architecture and platform
			dependent.

	2) /sys/devices/system/cpu/cpuX/topology/core_id:		2) /sys/devices/system/cpu/cpuX/topology/core_id:
	represent the cpu core id to cpu X;
			the CPU core ID of cpuX. Typically it is the hardware platform's
			identifier (rather than the kernel's). The actual value is
			architecture and platform dependent.

	3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:		3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
	represent the thread siblings to cpu X in the same core;
			internel kernel map of cpuX's hardware threads within the same
			core as cpuX

	4) /sys/devices/system/cpu/cpuX/topology/core_siblings:		4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
	represent the thread siblings to cpu X in the same physical package;
			internal kernel map of cpuX's hardware threads within the same
			physical_package_id.

	To implement it in an architecture-neutral way, a new source file,		To implement it in an architecture-neutral way, a new source file,
	drivers/base/topology.c, is to export the 4 attributes.		drivers/base/topology.c, is to export the 4 attributes.
	@@ -32,32 +45,32 @@ not defined by include/asm-XXX/topology.h:
	3) thread_siblings: just the given CPU		3) thread_siblings: just the given CPU
	4) core_siblings: just the given CPU		4) core_siblings: just the given CPU

	Additionally, cpu topology information is provided under		Additionally, CPU topology information is provided under
	/sys/devices/system/cpu and includes these files. The internal		/sys/devices/system/cpu and includes these files. The internal
	source for the output is in brackets ("[]").		source for the output is in brackets ("[]").

	kernel_max: the maximum cpu index allowed by the kernel configuration.		kernel_max: the maximum CPU index allowed by the kernel configuration.
	[NR_CPUS-1]		[NR_CPUS-1]

	offline: cpus that are not online because they have been		offline: CPUs that are not online because they have been
	HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit		HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit
	of cpus allowed by the kernel configuration (kernel_max		of CPUs allowed by the kernel configuration (kernel_max
	above). [~cpu_online_mask + cpus >= NR_CPUS]		above). [~cpu_online_mask + cpus >= NR_CPUS]

	online: cpus that are online and being scheduled [cpu_online_mask]		online: CPUs that are online and being scheduled [cpu_online_mask]

	possible: cpus that have been allocated resources and can be		possible: CPUs that have been allocated resources and can be
	brought online if they are present. [cpu_possible_mask]		brought online if they are present. [cpu_possible_mask]

	present: cpus that have been identified as being present in the		present: CPUs that have been identified as being present in the
	system. [cpu_present_mask]		system. [cpu_present_mask]

	The format for the above output is compatible with cpulist_parse()		The format for the above output is compatible with cpulist_parse()
	[see <linux/cpumask.h>]. Some examples follow.		[see <linux/cpumask.h>]. Some examples follow.

	In this example, there are 64 cpus in the system but cpus 32-63 exceed		In this example, there are 64 CPUs in the system but cpus 32-63 exceed
	the kernel max which is limited to 0..31 by the NR_CPUS config option		the kernel max which is limited to 0..31 by the NR_CPUS config option
	being 32. Note also that cpus 2 and 4-31 are not online but could be		being 32. Note also that CPUs 2 and 4-31 are not online but could be
	brought online as they are both present and possible.		brought online as they are both present and possible.

	kernel_max: 31		kernel_max: 31
	@@ -67,8 +80,8 @@ brought online as they are both present and possible.
	present: 0-31		present: 0-31

	In this example, the NR_CPUS config option is 128, but the kernel was		In this example, the NR_CPUS config option is 128, but the kernel was
	started with possible_cpus=144. There are 4 cpus in the system and cpu2		started with possible_cpus=144. There are 4 CPUs in the system and cpu2
	was manually taken offline (and is the only cpu that can be brought		was manually taken offline (and is the only CPU that can be brought
	online.)		online.)

	kernel_max: 127		kernel_max: 127
	@@ -78,4 +91,4 @@ online.)
	present: 0-3		present: 0-3

	See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter		See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter
	as well as more information on the various cpumask's.		as well as more information on the various cpumasks.