• Heiko Carstens's avatar
    s390/cache: expose cpu cache topology via sysfs · 881730ad
    Heiko Carstens authored
    Expose cpu cache topology via sysfs.
    The created sysfs directory structure is compatible to what x86, ia64
    and powerpc have.
    On s390 we expose only information about cpu caches which are private
    to a cpu via sysfs . Caches which are shared between cpus do not have
    a sysfs representation.
    The reason for that is that the file "shared_cpu_map" is mandatory
    and only if running under LPAR it is possible to tell which cpus
    share which cache. Second level hypervisors however do not and cannot
    expose that information to guests.
    In order to have a consistent view we made the choice to always only
    expose information about private cpu caches via sysfs.
    
    Example for a z196 cpu (cpu1 in /sys/devices/cpu):
    
    cpu1/cache/index0/size -- 64K
    cpu1/cache/index0/type -- Data
    cpu1/cache/index0/level -- 1
    cpu1/cache/index0/number_of_sets -- 64
    cpu1/cache/index0/shared_cpu_map -- 00000000,00000002
    cpu1/cache/index0/shared_cpu_list -- 1
    cpu1/cache/index0/coherency_line_size -- 256
    cpu1/cache/index0/ways_of_associativity -- 4
    cpu1/cache/index1/size -- 128K
    cpu1/cache/index1/type -- Instruction
    cpu1/cache/index1/level -- 1
    cpu1/cache/index1/number_of_sets -- 64
    cpu1/cache/index1/shared_cpu_map -- 00000000,00000002
    cpu1/cache/index1/shared_cpu_list -- 1
    cpu1/cache/index1/coherency_line_size -- 256
    cpu1/cache/index1/ways_of_associativity -- 8
    cpu1/cache/index2/size -- 1536K
    cpu1/cache/index2/type -- Unified
    cpu1/cache/index2/level -- 2
    cpu1/cache/index2/number_of_sets -- 512
    cpu1/cache/index2/shared_cpu_map -- 00000000,00000002
    cpu1/cache/index2/shared_cpu_list -- 1
    cpu1/cache/index2/coherency_line_size -- 256
    cpu1/cache/index2/ways_of_associativity -- 12
    Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
    Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
    881730ad
Makefile 1.93 KB