From: Nick Piggin <nickpiggin@yahoo.com.au>
Fix up active load balancing a bit so it doesn't get called when it shouldn't.
Reset the nr_balance_failed counter at more points where we have found
conditions to be balanced. This reduces too aggressive active balancing seen
on some workloads.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/kernel/sched.c | 16 ++++++++++------
1 files changed, 10 insertions(+), 6 deletions(-)
diff -puN kernel/sched.c~sched2-reduce-active-load-balancing kernel/sched.c
--- 25/kernel/sched.c~sched2-reduce-active-load-balancing 2005-03-17 23:47:58.000000000 -0800
+++ 25-akpm/kernel/sched.c 2005-03-17 23:47:58.000000000 -0800
@@ -2022,6 +2022,7 @@ out_balanced:
schedstat_inc(sd, lb_balanced[idle]);
+ sd->nr_balance_failed = 0;
/* tune up the balancing interval */
if (sd->balance_interval < sd->max_interval)
sd->balance_interval *= 2;
@@ -2047,16 +2048,14 @@ static int load_balance_newidle(int this
schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE);
if (!group) {
- schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
- goto out;
+ goto out_balanced;
}
busiest = find_busiest_queue(group);
if (!busiest || busiest == this_rq) {
- schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
- goto out;
+ goto out_balanced;
}
/* Attempt to move tasks */
@@ -2067,11 +2066,16 @@ static int load_balance_newidle(int this
imbalance, sd, NEWLY_IDLE, NULL);
if (!nr_moved)
schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
+ else
+ sd->nr_balance_failed = 0;
spin_unlock(&busiest->lock);
-
-out:
return nr_moved;
+
+out_balanced:
+ schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
+ sd->nr_balance_failed = 0;
+ return 0;
}
/*
_