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topology: Simplify cputopology.txt formatting and wording

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Syntax only, no functional or semantic change.

Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-doc@vger.kernel.org
Link: http://lkml.kernel.org/r/1ca56f8ea922a67f0017bd645912ea02a65a85ec.1551160674.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Len Brown 2019-02-26 01:20:00 -05:00 committed by Ingo Molnar
parent ef7c7727f2
commit 3a1c779fb8
1 changed files with 23 additions and 23 deletions
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46
Documentation/cputopology.txt
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@ -3,79 +3,79 @@ 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:
to /proc/cpuinfo output of some architectures. They reside in
/sys/devices/system/cpu/cpuX/topology/:
1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
physical_package_id:
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:
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.
3) /sys/devices/system/cpu/cpuX/topology/book_id:
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.
4) /sys/devices/system/cpu/cpuX/topology/drawer_id:
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.
5) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
thread_siblings:
internal kernel map of cpuX's hardware threads within the same
core as cpuX.
6) /sys/devices/system/cpu/cpuX/topology/thread_siblings_list:
thread_siblings_list:
human-readable list of cpuX's hardware threads within the same
core as cpuX.
7) /sys/devices/system/cpu/cpuX/topology/core_siblings:
core_siblings:
internal kernel map of cpuX's hardware threads within the same
physical_package_id.
8) /sys/devices/system/cpu/cpuX/topology/core_siblings_list:
core_siblings_list:
human-readable list of cpuX's hardware threads within the same
physical_package_id.
9) /sys/devices/system/cpu/cpuX/topology/book_siblings:
book_siblings:
internal kernel map of cpuX's hardware threads within the same
book_id.
10) /sys/devices/system/cpu/cpuX/topology/book_siblings_list:
book_siblings_list:
human-readable list of cpuX's hardware threads within the same
book_id.
11) /sys/devices/system/cpu/cpuX/topology/drawer_siblings:
drawer_siblings:
internal kernel map of cpuX's hardware threads within the same
drawer_id.
12) /sys/devices/system/cpu/cpuX/topology/drawer_siblings_list:
drawer_siblings_list:
human-readable list of cpuX's hardware threads within the same
drawer_id.
To implement it in an architecture-neutral way, a new source file,
drivers/base/topology.c, is to export the 6 to 12 attributes. The book
and drawer related sysfs files will only be created if CONFIG_SCHED_BOOK
and CONFIG_SCHED_DRAWER are selected.
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_DRAWER are currently only used on s390, where
they reflect the cpu and cache hierarchy.
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::
@ -98,10 +98,10 @@ 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) physical_package_id: -1
2) core_id: 0
3) sibling_cpumask: just the given CPU
4) core_cpumask: just the given CPU
1) topology_physical_package_id: -1
2) topology_core_id: 0
3) topology_sibling_cpumask: just the given CPU
4) topology_core_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().