• Ingo Molnar's avatar
    [PATCH] Introduce CONFIG_DEFAULT_MIGRATION_COST · 4bbf39c2
    Ingo Molnar authored
    Heiko Carstens <heiko.carstens@de.ibm.com> wrote:
    
      The boot sequence on s390 sometimes takes ages and we spend a very long
      time (up to one or two minutes) in calibrate_migration_costs.  The time
      spent there differs from boot to boot.  Also the calculated costs differ
      a lot.  I've seen differences by up to a factor of 15 (yes, factor not
      percent).  Also I doubt that making these measurements make much sense on
      a completely virtualized architecture where you cannot tell how much cpu
      time you will get anyway.
    
    So introduce the CONFIG_DEFAULT_MIGRATION_COST method for an architecture
    to set the scheduler migration costs.  This turns off automatic detection
    of migration costs.  Makes sense on virtual platforms, where migration
    costs are hard to measure accurately.
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    4bbf39c2
sched.c 153 KB