1. 21 Jun, 2009 1 commit
    • Andreas Herrmann's avatar
      x86: Set cpu_llc_id on AMD CPUs · 99bd0c0f
      Andreas Herrmann authored
      This counts when building sched domains in case NUMA information
      is not available.
      
      ( See cpu_coregroup_mask() which uses llc_shared_map which in turn is
        created based on cpu_llc_id. )
      
      Currently Linux builds domains as follows:
      (example from a dual socket quad-core system)
      
       CPU0 attaching sched-domain:
        domain 0: span 0-7 level CPU
         groups: 0 1 2 3 4 5 6 7
      
        ...
      
       CPU7 attaching sched-domain:
        domain 0: span 0-7 level CPU
         groups: 7 0 1 2 3 4 5 6
      
      Ever since that is borked for multi-core AMD CPU systems.
      This patch fixes that and now we get a proper:
      
       CPU0 attaching sched-domain:
        domain 0: span 0-3 level MC
         groups: 0 1 2 3
         domain 1: span 0-7 level CPU
          groups: 0-3 4-7
      
        ...
      
       CPU7 attaching sched-domain:
        domain 0: span 4-7 level MC
         groups: 7 4 5 6
         domain 1: span 0-7 level CPU
          groups: 4-7 0-3
      
      This allows scheduler to assign tasks to cores on different sockets
      (i.e. that don't share last level cache) for performance reasons.
      Signed-off-by: default avatarAndreas Herrmann <andreas.herrmann3@amd.com>
      LKML-Reference: <20090619085909.GJ5218@alberich.amd.com>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      99bd0c0f
  2. 20 Jun, 2009 39 commits