From 69dcc99199fe29b0a29471a3488d39d9d33b25fc Mon Sep 17 00:00:00 2001 From: "Zhang, Yanmin" Date: Fri, 3 Feb 2006 03:04:36 -0800 Subject: [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 Cc: Ingo Molnar Cc: Nick Piggin Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/cputopology.txt | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 Documentation/cputopology.txt (limited to 'Documentation/cputopology.txt') diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt new file mode 100644 index 00000000000..ff280e2e161 --- /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. + -- cgit v1.2.3