Eric Lee / smarc-fsl-linux-kernel

04 Oct, 2006

1 commit

29 Mar, 2006

1 commit

04 Feb, 2006

1 commit

  • 69dcc9919   [PATCH] Export cpu topology in sysfs ... Browse Code »

    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

    Zhang, Yanmin