Commit Graph

16 Commits

Author SHA1 Message Date
Ingo Molnar
5870db5b83 sched: remove the 'u64 now' parameter from update_stats_wait_start()
remove the 'u64 now' parameter from update_stats_wait_start().

( identity transformation that causes no change in functionality. )

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Ingo Molnar
b7cc089657 sched: remove the 'u64 now' parameter from update_curr()
remove the 'u64 now' parameter from update_curr().

( identity transformation that causes no change in functionality. )

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Ingo Molnar
5cef9eca38 sched: remove the 'u64 now' parameter from print_cfs_rq()
remove the 'u64 now' parameter from print_cfs_rq().

( identity transformation that causes no change in functionality. )

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Ingo Molnar
d281918d7c sched: remove 'now' use from assignments
change all 'now' timestamp uses in assignments to rq->clock.

( this is an identity transformation that causes no functionality change:
  all such new rq->clock is necessarily preceded by an update_rq_clock()
  call. )

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Ingo Molnar
c1b3da3ecd sched: eliminate __rq_clock() use
eliminate __rq_clock() use by changing it to:

   __update_rq_clock(rq)
   now = rq->clock;

identity transformation - no change in behavior.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Ingo Molnar
a8e504d2a5 sched: eliminate rq_clock() use
eliminate rq_clock() use by changing it to:

   update_rq_clock(rq)
   now = rq->clock;

identity transformation - no change in behavior.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:47 +02:00
Peter Williams
a4ac01c36e sched: fix bug in balance_tasks()
There are two problems with balance_tasks() and how it used:

1. The variables best_prio and best_prio_seen (inherited from the old
move_tasks()) were only required to handle problems caused by the
active/expired arrays, the order in which they were processed and the
possibility that the task with the highest priority could be on either.
  These issues are no longer present and the extra overhead associated
with their use is unnecessary (and possibly wrong).

2. In the absence of CONFIG_FAIR_GROUP_SCHED being set, the same
this_best_prio variable needs to be used by all scheduling classes or
there is a risk of moving too much load.  E.g. if the highest priority
task on this at the beginning is a fairly low priority task and the rt
class migrates a task (during its turn) then that moved task becomes the
new highest priority task on this_rq but when the sched_fair class
initializes its copy of this_best_prio it will get the priority of the
original highest priority task as, due to the run queue locks being
held, the reschedule triggered by pull_task() will not have taken place.
  This could result in inappropriate overriding of skip_for_load and
excessive load being moved.

The attached patch addresses these problems by deleting all reference to
best_prio and best_prio_seen and making this_best_prio a reference
parameter to the various functions involved.

load_balance_fair() has also been modified so that this_best_prio is
only reset (in the loop) if CONFIG_FAIR_GROUP_SCHED is set.  This should
preserve the effect of helping spread groups' higher priority tasks
around the available CPUs while improving system performance when
CONFIG_FAIR_GROUP_SCHED isn't set.

Signed-off-by: Peter Williams <pwil3058@bigpond.net.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:46 +02:00
Ingo Molnar
fd8bb43e27 sched: delta_exec accounting fix
small delta_exec accounting fix: increase delta_exec and increase
sum_exec_runtime even if the task is not on the runqueue anymore.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:46 +02:00
Ingo Molnar
c5dcfe72aa sched: clean up delta_mine
cleanup: delta_mine is an unsigned value.

no code impact:

   text    data     bss     dec     hex filename
   27823    2726      16   30565    7765 sched.o.before
   27823    2726      16   30565    7765 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:46 +02:00
Josh Triplett
291ae5a120 sched: mark print_cfs_stats static
sched_fair.c defines print_cfs_stats, and sched_debug.c uses it, but sched.c
includes both sched_fair.c and sched_debug.c, so all the references to
print_cfs_stats occur in the same compilation unit.  Thus, mark
print_cfs_stats static.

Eliminates a sparse warning:
warning: symbol 'print_cfs_stats' was not declared. Should it be static?

Signed-off-by: Josh Triplett <josh@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:46 +02:00
Peter Williams
4301065920 sched: simplify move_tasks()
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: Peter Williams <pwil3058@bigpond.net.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:46 +02:00
Ingo Molnar
0915c4e89d sched: batch sleeper bonus
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: Ingo Molnar <mingo@elte.hu>
2007-08-09 11:16:45 +02:00
Ingo Molnar
6cfb0d5d06 [PATCH] sched: reduce debug code
move the rest of the debugging/instrumentation code to under
CONFIG_SCHEDSTATS too. This reduces code size and speeds code up:

    text    data     bss     dec     hex filename
   33044    4122      28   37194    914a sched.o.before
   32708    4122      28   36858    8ffa sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-02 17:41:40 +02:00
Ingo Molnar
8179ca23d5 [PATCH] sched: use schedstat_set() API
make use of the new schedstat_set() API to eliminate two #ifdef sections.

No functional changes:

    text    data     bss     dec     hex filename
   29009    4122      28   33159    8187 sched.o.before
   29009    4122      28   33159    8187 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-02 17:41:40 +02:00
Ingo Molnar
cad60d93e1 [PATCH] sched: ->task_new cleanup
make sched_class.task_new == NULL a 'default method', this
allows the removal of task_rt_new.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-02 17:41:40 +02:00
Ingo Molnar
bf0f6f24a1 sched: cfs core, kernel/sched_fair.c
add kernel/sched_fair.c - which implements the bulk of CFS's
behavioral changes for SCHED_OTHER tasks.

see Documentation/sched-design-CFS.txt about details.

Authors:

 Ingo Molnar <mingo@elte.hu>
 Dmitry Adamushko <dmitry.adamushko@gmail.com>
 Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
 Mike Galbraith <efault@gmx.de>

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
2007-07-09 18:51:58 +02:00