[PATCH 13/30] sched: no need to aggregate task_weight

Peter Zijlstra
2008-06-27T11:59:27Z

[-- Attachment #1: sched-agg-no-task_weight.patch --]
[-- Type: text/plain, Size: 2016 bytes --]

We only need to know the task_weight of the busiest rq - nothing to do
if there are no tasks there.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
kernel/sched.c | 16 +---------------
kernel/sched_fair.c | 2 +-
2 files changed, 2 insertions(+), 16 deletions(-)

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -432,12 +432,6 @@ struct cfs_rq {
* The sum of all runqueue weights within this span.
*/
unsigned long rq_weight;
-
- /*
- * Weight contributed by tasks; this is the part we can
- * influence by moving tasks around.
- */
- unsigned long task_weight;
} aggregate;
#endif
#endif
@@ -1483,10 +1477,6 @@ static int task_hot(struct task_struct *
* rq_weight:
* Direct sum of all the cpu's their rq weight, e.g. A would get 3 while
* B would get 2.
- *
- * task_weight:
- * Part of the rq_weight contributed by tasks; all groups except B would
- * get 1, B gets 2.
*/

static inline struct aggregate_struct *
@@ -1534,16 +1524,12 @@ static void
aggregate_group_weight(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long rq_weight = 0;
- unsigned long task_weight = 0;
int i;

- for_each_cpu_mask(i, sd->span) {
+ for_each_cpu_mask(i, sd->span)
rq_weight += tg->cfs_rq[i]->load.weight;
- task_weight += tg->cfs_rq[i]->task_weight;
- }

aggregate(tg, cpu)->rq_weight = rq_weight;
- aggregate(tg, cpu)->task_weight = task_weight;
}

/*
Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -1418,7 +1418,7 @@ load_balance_fair(struct rq *this_rq, in
/*
* empty group
*/
- if (!aggregate(tg, this_cpu)->task_weight)
+ if (!tg->cfs_rq[busiest_cpu]->task_weight)
continue;

rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight;

--