diff options
Diffstat (limited to 'Documentation/cputopology.txt')
| -rw-r--r-- | Documentation/cputopology.txt | 37 |
1 files changed, 27 insertions, 10 deletions
diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt index 0aad6deb2d96..12b1b25b4da9 100644 --- a/Documentation/cputopology.txt +++ b/Documentation/cputopology.txt @@ -1,6 +1,6 @@ Export CPU topology info via sysfs. Items (attributes) are similar -to /proc/cpuinfo. +to /proc/cpuinfo output of some architectures: 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id: @@ -23,20 +23,35 @@ to /proc/cpuinfo. 4) /sys/devices/system/cpu/cpuX/topology/thread_siblings: internal kernel map of cpuX's hardware threads within the same - core as cpuX + core as cpuX. -5) /sys/devices/system/cpu/cpuX/topology/core_siblings: +5) /sys/devices/system/cpu/cpuX/topology/thread_siblings_list: + + human-readable list of cpuX's hardware threads within the same + core as cpuX. + +6) /sys/devices/system/cpu/cpuX/topology/core_siblings: internal kernel map of cpuX's hardware threads within the same physical_package_id. -6) /sys/devices/system/cpu/cpuX/topology/book_siblings: +7) /sys/devices/system/cpu/cpuX/topology/core_siblings_list: + + human-readable list of cpuX's hardware threads within the same + physical_package_id. + +8) /sys/devices/system/cpu/cpuX/topology/book_siblings: internal kernel map of cpuX's hardware threads within the same book_id. +9) /sys/devices/system/cpu/cpuX/topology/book_siblings_list: + + human-readable list of cpuX's hardware threads within the same + book_id. + To implement it in an architecture-neutral way, a new source file, -drivers/base/topology.c, is to export the 4 or 6 attributes. The two book +drivers/base/topology.c, is to export the 6 or 9 attributes. The three book related sysfs files will only be created if CONFIG_SCHED_BOOK is selected. For an architecture to support this feature, it must define some of @@ -44,20 +59,22 @@ these macros in include/asm-XXX/topology.h: #define topology_physical_package_id(cpu) #define topology_core_id(cpu) #define topology_book_id(cpu) -#define topology_thread_cpumask(cpu) +#define topology_sibling_cpumask(cpu) #define topology_core_cpumask(cpu) #define topology_book_cpumask(cpu) -The type of **_id is int. -The type of siblings is (const) struct cpumask *. +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) physical_package_id: -1 2) core_id: 0 -3) thread_siblings: just the given CPU -4) core_siblings: just the given CPU +3) sibling_cpumask: just the given CPU +4) 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(). |