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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	lkml <linux-kernel@vger.kernel.org>,
	Mike Galbraith <efault@gmx.de>
Subject: Re: Regression in latest sched-git
Date: Thu, 14 Feb 2008 12:20:41 +0100	[thread overview]
Message-ID: <1202988041.6297.6.camel@lappy> (raw)
In-Reply-To: <20080212185355.GA6320@linux.vnet.ibm.com>

Hi Dhaval,

How does this patch (on top of todays sched-devel.git) work for you?

It keeps my laptop nice and spiffy when I run

let i=0; while [ $i -lt 100 ]; do let i+=1; while :; do :; done & done

under a third user (nobody). This generates huge latencies for the nobody 
user (up to 1.6s) but root and peter don't seem to get above 40ms

---
 include/linux/sched.h |    1 +
 kernel/sched_fair.c   |    6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)

Index: linux-2.6/include/linux/sched.h
===================================================================
--- linux-2.6.orig/include/linux/sched.h
+++ linux-2.6/include/linux/sched.h
@@ -925,6 +925,7 @@ struct sched_entity {
 	u64			exec_start;
 	u64			sum_exec_runtime;
 	u64			vruntime;
+	u64			vperiod;
 	u64			prev_sum_exec_runtime;
 
 #ifdef CONFIG_SCHEDSTATS
Index: linux-2.6/kernel/sched_fair.c
===================================================================
--- linux-2.6.orig/kernel/sched_fair.c
+++ linux-2.6/kernel/sched_fair.c
@@ -220,9 +220,11 @@ static inline u64 min_vruntime(u64 min_v
 
 static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-	return se->vruntime - cfs_rq->min_vruntime;
+	return se->vruntime + se->vperiod - cfs_rq->min_vruntime;
 }
 
+static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se);
+
 /*
  * Enqueue an entity into the rb-tree:
  */
@@ -240,6 +242,8 @@ static void __enqueue_entity(struct cfs_
 	if (se == cfs_rq->curr)
 		return;
 
+	se->vperiod = sched_vslice_add(cfs_rq, se);
+
 	cfs_rq = &rq_of(cfs_rq)->cfs;
 
 	link = &cfs_rq->tasks_timeline.rb_node;



      parent reply	other threads:[~2008-02-14 11:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-12 18:53 Dhaval Giani
2008-02-12 19:40 ` Peter Zijlstra
2008-02-13  3:00   ` Srivatsa Vaddagiri
2008-02-13 12:51     ` Peter Zijlstra
2008-02-13 16:34       ` Dhaval Giani
2008-02-13 16:37         ` Dhaval Giani
2008-02-13 16:43           ` Peter Zijlstra
2008-02-13 17:06         ` Srivatsa Vaddagiri
2008-02-14 11:20 ` Peter Zijlstra [this message]

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