From: Nick Piggin <piggin@cyberone.com.au>
I think this might be causing problems. Maybe its there for a reason, but
if so then I think some more work needs to be done.
An idle CPU will be unable to pull tasks from a runqueue if they have all
been run very recently. This patch changes that. Maybe it overbalances on
other loads. It would be good to try those benchmarks on it...
kernel/sched.c | 16 +++++++++-------
1 files changed, 9 insertions(+), 7 deletions(-)
diff -puN kernel/sched.c~sched-cpu-migration-fix kernel/sched.c
--- 25/kernel/sched.c~sched-cpu-migration-fix 2003-08-30 15:42:08.000000000 -0700
+++ 25-akpm/kernel/sched.c 2003-08-30 15:42:08.000000000 -0700
@@ -1276,15 +1276,17 @@ static void rebalance_tick(runqueue_t *t
load_balance(this_rq, idle, cpu_to_node_mask(this_cpu));
spin_unlock(&this_rq->lock);
}
- }
+
+ } else {
#ifdef CONFIG_NUMA
- if (!(j % BUSY_NODE_REBALANCE_TICK))
- balance_node(this_rq, idle, this_cpu);
+ if (!(j % BUSY_NODE_REBALANCE_TICK))
+ balance_node(this_rq, idle, this_cpu);
#endif
- if (!(j % BUSY_REBALANCE_TICK)) {
- spin_lock(&this_rq->lock);
- load_balance(this_rq, 0, cpu_to_node_mask(this_cpu));
- spin_unlock(&this_rq->lock);
+ if (!(j % BUSY_REBALANCE_TICK)) {
+ spin_lock(&this_rq->lock);
+ load_balance(this_rq, idle, cpu_to_node_mask(this_cpu));
+ spin_unlock(&this_rq->lock);
+ }
}
}
#else
_