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  1. 09 Aug, 2007 5 commits
    • Ulrich Drepper's avatar
      sched: clean up sched_getaffinity() · 9531b62f
      Ulrich Drepper authored 
      here's another tiny cleanup.  The generated code is not affected (gcc is
smart enough) but for people looking over the code it is just irritating
to have the extra conditional.
Signed-off-by: default avatarUlrich Drepper <drepper@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9531b62f
    • 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
  3. 07 Aug, 2007 9 commits
  5. 06 Aug, 2007 3 commits
  7. 05 Aug, 2007 2 commits
  9. 04 Aug, 2007 14 commits
  11. 03 Aug, 2007 7 commits
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