linux.git/kernel/sched_idletask.c, branch v2.6.26-rc7

sched: make rt_sched_class, idle_sched_class static

2008-05-05T21:56:17+00:00

The C files are included directly in sched.c, so they are
effectively static.

Signed-off-by: Harvey Harrison 
Acked-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

sched: high-res preemption tick

2008-01-25T20:08:29+00:00

Use HR-timers (when available) to deliver an accurate preemption tick.

The regular scheduler tick that runs at 1/HZ can be too coarse when nice
level are used. The fairness system will still keep the cpu utilisation 'fair'
by then delaying the task that got an excessive amount of CPU time but try to
minimize this by delivering preemption points spot-on.

The average frequency of this extra interrupt is sched_latency / nr_latency.
Which need not be higher than 1/HZ, its just that the distribution within the
sched_latency period is important.

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

sched: RT-balance, add new methods to sched_class

2008-01-25T20:08:22+00:00

Dmitry Adamushko found that the current implementation of the RT
balancing code left out changes to the sched_setscheduler and
rt_mutex_setprio.

This patch addresses this issue by adding methods to the schedule classes
to handle being switched out of (switched_from) and being switched into
(switched_to) a sched_class. Also a method for changing of priorities
is also added (prio_changed).

This patch also removes some duplicate logic between rt_mutex_setprio and
sched_setscheduler.

Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

sched: de-SCHED_OTHER-ize the RT path

2008-01-25T20:08:09+00:00

The current wake-up code path tries to determine if it can optimize the
wake-up to "this_cpu" by computing load calculations.  The problem is that
these calculations are only relevant to SCHED_OTHER tasks where load is king.
For RT tasks, priority is king.  So the load calculation is completely wasted
bandwidth.

Therefore, we create a new sched_class interface to help with
pre-wakeup routing decisions and move the load calculation as a function
of CFS task's class.

Signed-off-by: Gregory Haskins 
Signed-off-by: Steven Rostedt 
Signed-off-by: Ingo Molnar

sched: isolate SMP balancing code a bit more

2007-10-24T16:23:51+00:00

At the moment, a lot of load balancing code that is irrelevant to non
SMP systems gets included during non SMP builds.

This patch addresses this issue and reduces the binary size on non
SMP systems:

   text    data     bss     dec     hex filename
  10983      28    1192   12203    2fab sched.o.before
  10739      28    1192   11959    2eb7 sched.o.after

Signed-off-by: Peter Williams 
Signed-off-by: Ingo Molnar

sched: reduce balance-tasks overhead

2007-10-24T16:23:51+00:00

At the moment, balance_tasks() provides low level functionality for both
  move_tasks() and move_one_task() (indirectly) via the load_balance()
function (in the sched_class interface) which also provides dual
functionality.  This dual functionality complicates the interfaces and
internal mechanisms and makes the run time overhead of operations that
are called with two run queue locks held.

This patch addresses this issue and reduces the overhead of these
operations.

Signed-off-by: Peter Williams 
Signed-off-by: Ingo Molnar

sched: mark scheduling classes as const

2007-10-15T15:00:12+00:00

mark scheduling classes as const. The speeds up the code
a bit and shrinks it:

   text    data     bss     dec     hex filename
  40027    4018     292   44337    ad31 sched.o.before
  40190    3842     292   44324    ad24 sched.o.after

Signed-off-by: Ingo Molnar 
Reviewed-by: Thomas Gleixner

sched: revert recent removal of set_curr_task()

2007-10-15T15:00:08+00:00

Revert removal of set_curr_task.
Use put_prev_task/set_curr_task when changing groups/policies

Signed-off-by: Srivatsa Vaddagiri < vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani 
Signed-off-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra

sched: rework enqueue/dequeue_entity() to get rid of set_curr_task()

2007-10-15T15:00:08+00:00

rework enqueue/dequeue_entity() to get rid of 
sched_class::set_curr_task(). This simplifies sched_setscheduler(), 
rt_mutex_setprio() and sched_move_tasks().

   text    data     bss     dec     hex filename
  24330    2734      20   27084    69cc sched.o.before
  24233    2730      20   26983    6967 sched.o.after

Signed-off-by: Dmitry Adamushko 
Signed-off-by: Srivatsa Vaddagiri 
Signed-off-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
Reviewed-by: Thomas Gleixner

sched: group-scheduler core

2007-10-15T15:00:07+00:00

Add interface to control cpu bandwidth allocation to task-groups.

(not yet configurable, due to missing CONFIG_CONTAINERS)

Signed-off-by: Srivatsa Vaddagiri 
Signed-off-by: Dhaval Giani 
Signed-off-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra