[PATCH] sched: decrease number of load balances

Currently at a particular domain, each cpu in the sched group will do a
load balance at the frequency of balance_interval.  More the cores and
threads, more the cpus will be in each sched group at SMP and NUMA domain.
And we endup spending quite a bit of time doing load balancing in those
domains.

Fix this by making only one cpu(first idle cpu or first cpu in the group if
all the cpus are busy) in the sched group do the load balance at that
particular sched domain and this load will slowly percolate down to the
other cpus with in that group(when they do load balancing at lower
domains).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index ea92e5c89089..72d6927d29ed 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -707,6 +707,7 @@ struct sched_domain {
         unsigned long lb_hot_gained[MAX_IDLE_TYPES];
         unsigned long lb_nobusyg[MAX_IDLE_TYPES];
         unsigned long lb_nobusyq[MAX_IDLE_TYPES];
+        unsigned long lb_stopbalance[MAX_IDLE_TYPES];
 
         /* Active load balancing */
         unsigned long alb_cnt;