7/13
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 <[EMAIL PROTECTED]>
Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c 2005-02-24 17:39:05.851128944 +1100
+++ linux-2.6/kernel/sched.c 2005-02-24 17:43:38.162526682 +1100
@@ -2009,6 +2009,7 @@
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;
@@ -2034,16 +2035,14 @@
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 */
@@ -2054,11 +2053,16 @@
imbalance, sd, NEWLY_IDLE, &all_pinned);
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;
}
/*
