Re: Performance regression of specjbb2005/aim7 with 2.6.29-rc1

[Peter Zijlstra <peterz@infradead.org>]

On Thu, 2009-01-15 at 10:30 +0800, Lin Ming wrote:

> Below patch fixes aim7 regression and specjbb2005 regression becomes
> less than 1.5% on 8-core stokley.

Ingo, please apply the below.

Ming, would you also provide a S-o-b line?

---
Subject: sched_slice fixlet
From: Lin Ming <ming.m.lin@intel.com>
Date: Thu Jan 15 17:10:02 CET 2009

Mike's change: 0a582440f -- sched: fix sched_slice())
Broke group scheduling by forgetting to reload cfs_rq on each loop.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 kernel/sched_fair.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -429,7 +429,10 @@ static u64 sched_slice(struct cfs_rq *cf
 	u64 slice = __sched_period(cfs_rq->nr_running + !se->on_rq);
 
 	for_each_sched_entity(se) {
-		struct load_weight *load = &cfs_rq->load;
+		struct load_weight *load;
+
+		cfs_rq = cfs_rq_of(se);
+		load = &cfs_rq->load;
 
 		if (unlikely(!se->on_rq)) {
 			struct load_weight lw = cfs_rq->load;