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author | Zhang, Yanmin <yanmin.zhang@intel.com> | 2006-02-03 14:04:36 +0300 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-03 19:32:09 +0300 |
commit | 69dcc99199fe29b0a29471a3488d39d9d33b25fc (patch) | |
tree | 4232ad9a782dee6abfe7fa20c95a49249195de8f /Documentation | |
parent | 66ac5a294db70aa377c0d7bbdb0c4e3ef2349b7b (diff) | |
download | linux-69dcc99199fe29b0a29471a3488d39d9d33b25fc.tar.xz |
[PATCH] Export cpu topology in sysfs
The patch implements cpu topology exportation by 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,
driver/base/topology.c, is to export the 5 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.
Thank Nathan, Greg, Andi, Paul and Venki.
The patch provides defines for i386/x86_64/ia64.
Signed-off-by: Zhang, Yanmin <yanmin.zhang@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/cputopology.txt | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt new file mode 100644 index 000000000000..ff280e2e1613 --- /dev/null +++ b/Documentation/cputopology.txt @@ -0,0 +1,41 @@ + +Export cpu topology info by 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, +driver/base/topology.c, is to export the 5 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. + |