1. 09 Aug, 2007 4 commits
    • Thomas Voegtle's avatar
      sched: mention CONFIG_SCHED_DEBUG in documentation · 5f5d3aa1
      Thomas Voegtle authored
      a little hint to switch on CONFIG_SCHED_DEBUG should be given.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      5f5d3aa1
    • Peter Williams's avatar
      sched: simplify move_tasks() · 43010659
      Peter Williams authored
      The move_tasks() function is currently multiplexed with two distinct
      capabilities:
      
      1. attempt to move a specified amount of weighted load from one run
      queue to another; and
      2. attempt to move a specified number of tasks from one run queue to
      another.
      
      The first of these capabilities is used in two places, load_balance()
      and load_balance_idle(), and in both of these cases the return value of
      move_tasks() is used purely to decide if tasks/load were moved and no
      notice of the actual number of tasks moved is taken.
      
      The second capability is used in exactly one place,
      active_load_balance(), to attempt to move exactly one task and, as
      before, the return value is only used as an indicator of success or failure.
      
      This multiplexing of sched_task() was introduced, by me, as part of the
      smpnice patches and was motivated by the fact that the alternative, one
      function to move specified load and one to move a single task, would
      have led to two functions of roughly the same complexity as the old
      move_tasks() (or the new balance_tasks()).  However, the new modular
      design of the new CFS scheduler allows a simpler solution to be adopted
      and this patch addresses that solution by:
      
      1. adding a new function, move_one_task(), to be used by
      active_load_balance(); and
      2. making move_tasks() a single purpose function that tries to move a
      specified weighted load and returns 1 for success and 0 for failure.
      
      One of the consequences of these changes is that neither move_one_task()
      or the new move_tasks() care how many tasks sched_class.load_balance()
      moves and this enables its interface to be simplified by returning the
      amount of load moved as its result and removing the load_moved pointer
      from the argument list.  This helps simplify the new move_tasks() and
      slightly reduces the amount of work done in each of
      sched_class.load_balance()'s implementations.
      
      Further simplification, e.g. changes to balance_tasks(), are possible
      but (slightly) complicated by the special needs of load_balance_fair()
      so I've left them to a later patch (if this one gets accepted).
      
      NB Since move_tasks() gets called with two run queue locks held even
      small reductions in overhead are worthwhile.
      
      [ mingo@elte.hu ]
      
      this change also reduces code size nicely:
      
         text    data     bss     dec     hex filename
         39216    3618      24   42858    a76a sched.o.before
         39173    3618      24   42815    a73f sched.o.after
      Signed-off-by: default avatarPeter Williams <pwil3058@bigpond.net.au>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      43010659
    • Ingo Molnar's avatar
      sched: reorder update_cpu_load(rq) with the ->task_tick() call · f1a438d8
      Ingo Molnar authored
      Peter Williams suggested to flip the order of update_cpu_load(rq) with
      the ->task_tick() call. This is a NOP for the current scheduler (the
      two functions are independent of each other), ->task_tick() might
      create some state for update_cpu_load() in the future (or in PlugSched).
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      f1a438d8
    • Ingo Molnar's avatar
      sched: batch sleeper bonus · 0915c4e8
      Ingo Molnar authored
      batch up the sleeper bonus sum a bit more. Anything below
      sched-granularity is too small to make a practical difference
      anyway.
      
      this optimization reduces the math in high-frequency scheduling
      scenarios.
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0915c4e8
  2. 07 Aug, 2007 9 commits
  3. 06 Aug, 2007 3 commits
  4. 05 Aug, 2007 2 commits
  5. 04 Aug, 2007 14 commits
  6. 03 Aug, 2007 8 commits