mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-27 06:34:11 +08:00
ded23ac627
Fix a few trivial mistakes in Documentation/cputopology.txt Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
42 lines
1.6 KiB
Plaintext
42 lines
1.6 KiB
Plaintext
|
|
Export cpu topology info via sysfs. Items (attributes) are similar
|
|
to /proc/cpuinfo.
|
|
|
|
1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
|
|
represent the physical package id of cpu X;
|
|
2) /sys/devices/system/cpu/cpuX/topology/core_id:
|
|
represent the cpu core id to cpu X;
|
|
3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
|
|
represent the thread siblings to cpu X in the same core;
|
|
4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
|
|
represent the thread siblings to cpu X in the same physical package;
|
|
|
|
To implement it in an architecture-neutral way, a new source file,
|
|
drivers/base/topology.c, is to export the 4 attributes.
|
|
|
|
If one architecture wants to support this feature, it just needs to
|
|
implement 4 defines, typically in file include/asm-XXX/topology.h.
|
|
The 4 defines are:
|
|
#define topology_physical_package_id(cpu)
|
|
#define topology_core_id(cpu)
|
|
#define topology_thread_siblings(cpu)
|
|
#define topology_core_siblings(cpu)
|
|
|
|
The type of **_id is int.
|
|
The type of siblings is cpumask_t.
|
|
|
|
To be consistent on all architectures, the 4 attributes should have
|
|
deafult values if their values are unavailable. Below is the rule.
|
|
1) physical_package_id: If cpu has no physical package id, -1 is the
|
|
default value.
|
|
2) core_id: If cpu doesn't support multi-core, its core id is 0.
|
|
3) thread_siblings: Just include itself, if the cpu doesn't support
|
|
HT/multi-thread.
|
|
4) core_siblings: Just include itself, if the cpu doesn't support
|
|
multi-core and HT/Multi-thread.
|
|
|
|
So be careful when declaring the 4 defines in include/asm-XXX/topology.h.
|
|
|
|
If an attribute isn't defined on an architecture, it won't be exported.
|
|
|