diff options
author | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-06-27 14:56:51 -0300 |
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committer | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-07-15 11:03:02 -0300 |
commit | 4f4cfa6c560c93ba180c30675cf845e1597de44c (patch) | |
tree | 0bbe2ec9e6ef62ed2a347504dda50c6bdbe43703 /Documentation/cputopology.txt | |
parent | da82c92f1150f66afabf78d2c85ef9ac18dc6d38 (diff) |
docs: admin-guide: add a series of orphaned documents
There are lots of documents that belong to the admin-guide but
are on random places (most under Documentation root dir).
Move them to the admin guide.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Diffstat (limited to 'Documentation/cputopology.txt')
-rw-r--r-- | Documentation/cputopology.txt | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt deleted file mode 100644 index b90dafcc8237..000000000000 --- a/Documentation/cputopology.txt +++ /dev/null @@ -1,177 +0,0 @@ -=========================================== -How CPU topology info is exported via sysfs -=========================================== - -Export CPU topology info via sysfs. Items (attributes) are similar -to /proc/cpuinfo output of some architectures. They reside in -/sys/devices/system/cpu/cpuX/topology/: - -physical_package_id: - - physical package id of cpuX. Typically corresponds to a physical - socket number, but the actual value is architecture and platform - dependent. - -die_id: - - the CPU die ID of cpuX. Typically it is the hardware platform's - identifier (rather than the kernel's). The actual value is - architecture and platform dependent. - -core_id: - - 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. - -book_id: - - the book ID of cpuX. Typically it is the hardware platform's - identifier (rather than the kernel's). The actual value is - architecture and platform dependent. - -drawer_id: - - the drawer ID of cpuX. Typically it is the hardware platform's - identifier (rather than the kernel's). The actual value is - architecture and platform dependent. - -core_cpus: - - internal kernel map of CPUs within the same core. - (deprecated name: "thread_siblings") - -core_cpus_list: - - human-readable list of CPUs within the same core. - (deprecated name: "thread_siblings_list"); - -package_cpus: - - internal kernel map of the CPUs sharing the same physical_package_id. - (deprecated name: "core_siblings") - -package_cpus_list: - - human-readable list of CPUs sharing the same physical_package_id. - (deprecated name: "core_siblings_list") - -die_cpus: - - internal kernel map of CPUs within the same die. - -die_cpus_list: - - human-readable list of CPUs within the same die. - -book_siblings: - - internal kernel map of cpuX's hardware threads within the same - book_id. - -book_siblings_list: - - human-readable list of cpuX's hardware threads within the same - book_id. - -drawer_siblings: - - internal kernel map of cpuX's hardware threads within the same - drawer_id. - -drawer_siblings_list: - - human-readable list of cpuX's hardware threads within the same - drawer_id. - -Architecture-neutral, drivers/base/topology.c, exports these attributes. -However, the book and drawer related sysfs files will only be created if -CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are selected, respectively. - -CONFIG_SCHED_BOOK and CONFIG_SCHED_DRAWER are currently only used on s390, -where they reflect the cpu and cache hierarchy. - -For an architecture to support this feature, it must define some of -these macros in include/asm-XXX/topology.h:: - - #define topology_physical_package_id(cpu) - #define topology_die_id(cpu) - #define topology_core_id(cpu) - #define topology_book_id(cpu) - #define topology_drawer_id(cpu) - #define topology_sibling_cpumask(cpu) - #define topology_core_cpumask(cpu) - #define topology_die_cpumask(cpu) - #define topology_book_cpumask(cpu) - #define topology_drawer_cpumask(cpu) - -The type of ``**_id macros`` is int. -The type of ``**_cpumask macros`` is ``(const) struct cpumask *``. The latter -correspond with appropriate ``**_siblings`` sysfs attributes (except for -topology_sibling_cpumask() which corresponds with thread_siblings). - -To be consistent on all architectures, include/linux/topology.h -provides default definitions for any of the above macros that are -not defined by include/asm-XXX/topology.h: - -1) topology_physical_package_id: -1 -2) topology_die_id: -1 -3) topology_core_id: 0 -4) topology_sibling_cpumask: just the given CPU -5) topology_core_cpumask: just the given CPU -6) topology_die_cpumask: just the given CPU - -For architectures that don't support books (CONFIG_SCHED_BOOK) there are no -default definitions for topology_book_id() and topology_book_cpumask(). -For architectures that don't support drawers (CONFIG_SCHED_DRAWER) there are -no default definitions for topology_drawer_id() and topology_drawer_cpumask(). - -Additionally, CPU topology information is provided under -/sys/devices/system/cpu and includes these files. The internal -source for the output is in brackets ("[]"). - - =========== ========================================================== - kernel_max: the maximum CPU index allowed by the kernel configuration. - [NR_CPUS-1] - - offline: CPUs that are not online because they have been - HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit - of CPUs allowed by the kernel configuration (kernel_max - above). [~cpu_online_mask + cpus >= NR_CPUS] - - online: CPUs that are online and being scheduled [cpu_online_mask] - - possible: CPUs that have been allocated resources and can be - brought online if they are present. [cpu_possible_mask] - - present: CPUs that have been identified as being present in the - system. [cpu_present_mask] - =========== ========================================================== - -The format for the above output is compatible with cpulist_parse() -[see <linux/cpumask.h>]. Some examples follow. - -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 -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:: - - kernel_max: 31 - offline: 2,4-31,32-63 - online: 0-1,3 - possible: 0-31 - present: 0-31 - -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 -was manually taken offline (and is the only CPU that can be brought -online.):: - - kernel_max: 127 - offline: 2,4-127,128-143 - online: 0-1,3 - possible: 0-127 - present: 0-3 - -See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter -as well as more information on the various cpumasks. |