From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: hpa@zytor.com, tglx@linutronix.de, mingo@elte.hu,
ak@linux.intel.com, linux-kernel@vger.kernel.org
Subject: Re: Odd performance results
Date: Tue, 12 Jul 2016 08:05:29 -0700 [thread overview]
Message-ID: <20160712150529.GN7094@linux.vnet.ibm.com> (raw)
In-Reply-To: <20160712145551.GU30909@twins.programming.kicks-ass.net>
On Tue, Jul 12, 2016 at 04:55:51PM +0200, Peter Zijlstra wrote:
> On Sun, Jul 10, 2016 at 07:43:27AM -0700, Paul E. McKenney wrote:
> > On Sun, Jul 10, 2016 at 07:17:19AM +0200, Peter Zijlstra wrote:
> > >
> > >
> > > On 10 July 2016 06:26:39 CEST, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> > > >Hello!
> > > >
> > > >So I ran a quick benchmark which showed stair-step results. I
> > > >immediately
> > > >thought "Ah, this is due to CPU 0 and 1, 2 and 3, 4 and 5, and 6 and 7
> > > >being threads in a core." Then I thought "Wait, this is an x86!"
> > > >Then I dumped out cpu*/topology/thread_siblings_list, getting the
> > > >following:
> > > >
> > > > cpu0/topology/thread_siblings_list: 0-1
> > > > cpu1/topology/thread_siblings_list: 0-1
> > > > cpu2/topology/thread_siblings_list: 2-3
> > > > cpu3/topology/thread_siblings_list: 2-3
> > > > cpu4/topology/thread_siblings_list: 4-5
> > > > cpu5/topology/thread_siblings_list: 4-5
> > > > cpu6/topology/thread_siblings_list: 6-7
> > > > cpu7/topology/thread_siblings_list: 6-7
> > >
> > >
> > > I'm guessing this is an AMD bulldozer like machine?
> >
> > /proc/cpuinfo thinks otherwise:
> >
> > processor : 0
> > vendor_id : GenuineIntel
> > cpu family : 6
> > model : 60
> > model name : Intel(R) Core(TM) i7-4710MQ CPU @ 2.50GHz
>
> Weird, I've never seen an Intel box do that before... hpa, any idea? or
> is this just one weird BIOS.
;-)
It is a Lenovo W541 laptop, for whatever that might be worth. Roughly
on year old.
Thanx, Paul
next prev parent reply other threads:[~2016-07-12 15:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-10 4:26 Odd performance results Paul E. McKenney
2016-07-10 5:17 ` Peter Zijlstra
2016-07-10 14:43 ` Paul E. McKenney
2016-07-12 14:55 ` Peter Zijlstra
2016-07-12 15:05 ` Paul E. McKenney [this message]
2016-07-12 17:49 ` H. Peter Anvin
2016-07-12 18:26 ` Paul E. McKenney
2016-07-12 18:51 ` Peter Zijlstra
2016-07-12 19:10 ` [CRM114spam]: " Dr. David Alan Gilbert
2016-07-12 19:59 ` Paul E. McKenney
2016-07-13 7:20 ` Ingo Molnar
2016-07-13 7:18 ` Ingo Molnar
2016-07-13 12:27 ` Henrique de Moraes Holschuh
2016-07-13 12:33 ` Peter Zijlstra
2016-07-13 14:06 ` Paul E. McKenney
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