1. 28 Mar, 2006 1 commit
  2. 03 Feb, 2006 1 commit
    • Zhang, Yanmin's avatar
      [PATCH] Export cpu topology in sysfs · 69dcc991
      Zhang, Yanmin authored
      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: default avatarZhang, 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: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      69dcc991