From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: hackbench regression due to commit 9dfc6e68bfe6e
Date: Thu, 08 Apr 2010 10:09:55 +0200
Message-ID: <1270714195.2215.14.camel@edumazet-laptop>
References: <1269506457.4513.141.camel@alexs-hp.sh.intel.com>
	 <alpine.DEB.2.00.1003250942080.2670@router.home>
	 <1269570902.9614.92.camel@alexs-hp.sh.intel.com>
	 <1270114166.2078.107.camel@ymzhang.sh.intel.com>
	 <alpine.DEB.2.00.1004011050340.16531@router.home>
	 <1270195589.2078.116.camel@ymzhang.sh.intel.com>
	 <alpine.DEB.2.00.1004050853300.23149@router.home>
	 <i2z84144f021004051030k7ff5190cyc083aa12c552dfac@mail.gmail.com>
	 <4BBA8DF9.8010409@kernel.org>
	 <1270542497.2078.123.camel@ymzhang.sh.intel.com>
	 <alpine.DEB.2.00.1004061033330.18750@router.home>
	 <alpine.DEB.2.00.1004061552500.19151@router.home>
	 <1270591841.2091.170.camel@edumazet-laptop>
	 <1270607668.2078.259.camel@ymzhang.sh.intel.com>
	 <alpine.DEB.2.00.1004071130260.13261@router.home>
	 <4BBCB7B7.4040901@cs.helsinki.fi> <4BBCB868.2000705@cs.helsinki.fi>
	 <alpine.DEB.2.00.1004071319320.16159@router.home>
	 <1270665484.8141.47.camel@edumazet-laptop>
	 <1270688747.2078.383.camel@ymzhang.sh.intel.com>
	 <1270702774.8141.49.camel@edumazet-laptop>
	 <1270705153.8141.58.camel@edumazet-laptop>
	 <1270710019.2215.4.camel@edumazet-laptop>
	 <1270713290.2078.402.camel@ymzhang.sh.intel.com>
	 <1270713272.2215.6.camel@edumazet-laptop>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: QUOTED-PRINTABLE
Cc: Christoph Lameter <cl@linux-foundation.org>,
	Pekka Enberg <penberg@cs.helsinki.fi>,
	netdev <netdev@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
	alex.shi@intel.com,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Ma, Ling" <ling.ma@intel.com>,
	"Chen, Tim C" <tim.c.chen@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <1270713272.2215.6.camel@edumazet-laptop>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: netdev.vger.kernel.org

Le jeudi 08 avril 2010 =C3=A0 09:54 +0200, Eric Dumazet a =C3=A9crit :
> Le jeudi 08 avril 2010 =C3=A0 15:54 +0800, Zhang, Yanmin a =C3=A9crit=
 :
>=20
> > If there are 2 nodes in the machine, processes on node 0 will conta=
ct MCH of
> > node 1 to access memory of node 1. I suspect the MCH of node 1 migh=
t enter
> > a power-saving mode when all the cpus of node 1 are free. So the tr=
ansactions
> > from MCH 1 to MCH 0 has a larger latency.
> >=20
>=20
> Hmm, thanks for the hint, I will investigate this.

Oh well,=20

perf timechart record &

Instant crash

Call Trace:
 perf_trace_sched_switch+0xd5/0x120
 schedule+0x6b5/0x860
 retint_careful+0xd/0x21
=20
RIP ffffffff81010955 perf_arch_fetch_caller_regs+0x15/0x40
CR2: 00000000d21f1422