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authorChristoph Lameter <clameter@sgi.com>2006-12-10 02:20:19 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 09:55:42 -0800
commit4211a9a2e94a34df8c02bc39b7ec10678ad5c2ab (patch)
tree006f3678fbf181cfd172f9dc5cb9077c9efc4165
parent571f6d2fb0b1c04798df783db2ba85e96bcce43d (diff)
[PATCH] sched: remove staggering of load balancing
Timer interrupts already are staggered. We do not need an additional layer of time staggering for short load balancing actions that take a reasonably small portion of the time slice. For load balancing on large sched_domains we will add a serialization later that avoids concurrent load balance operations and thus has the same effect as load staggering. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/sched.c10
1 files changed, 2 insertions, 8 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index fdd26fffaa2..b5b35013500 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2841,16 +2841,10 @@ static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
* Balancing parameters are set up in arch_init_sched_domains.
*/
-/* Don't have all balancing operations going off at once: */
-static inline unsigned long cpu_offset(int cpu)
-{
- return jiffies + cpu * HZ / NR_CPUS;
-}
-
static void
rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
{
- unsigned long this_load, interval, j = cpu_offset(this_cpu);
+ unsigned long this_load, interval;
struct sched_domain *sd;
int i, scale;
@@ -2885,7 +2879,7 @@ rebalance_tick(int this_cpu, struct rq *this_rq, enum idle_type idle)
if (unlikely(!interval))
interval = 1;
- if (j - sd->last_balance >= interval) {
+ if (jiffies - sd->last_balance >= interval) {
if (load_balance(this_cpu, this_rq, sd, idle)) {
/*
* We've pulled tasks over so either we're no