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From: Peter Zijlstra <peterz@infradead.org>
To: paulmck@linux.vnet.ibm.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
	"Luck, Tony" <tony.luck@intel.com>,
	"Yu, Fenghua" <fenghua.yu@intel.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Ingo Molnar <mingo@elte.hu>, H Peter Anvin <hpa@zytor.com>,
	"Siddha, Suresh B" <suresh.b.siddha@intel.com>,
	"Mallick, Asit K" <asit.k.mallick@intel.com>,
	Arjan Dan De Ven <arjan@linux.intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>, x86 <x86@kernel.org>,
	linux-pm <linux-pm@vger.kernel.org>,
	"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Subject: Re: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi
Date: Wed, 06 Jun 2012 14:17:21 +0200	[thread overview]
Message-ID: <1338985041.2749.107.camel@twins> (raw)
In-Reply-To: <20120605220059.GV2388@linux.vnet.ibm.com>

On Tue, 2012-06-05 at 15:00 -0700, Paul E. McKenney wrote:
> On Tue, Jun 05, 2012 at 11:37:21PM +0200, Peter Zijlstra wrote:
> > On Tue, 2012-06-05 at 14:29 -0700, Paul E. McKenney wrote:
> > > OK, I'll bite...  Why not just use CPU hotplug to expel the timers?
> > 
> > Currently? Can you say: 'kstopmachine'?
> 
> So if CPU hotplug (or whatever you want to call it) stops using
> kstopmachine, you are OK with it?

It would be much better, still not ideal though.

> > But its also a question of interface and naming. Do you want to have to
> > iterate all cpus in your isolated set, do you want to bring them down
> > far enough to physically unplug. Ideally no to both.
> 
> For many use cases, it is indeed not necessary to get to a point where
> the CPUs could be physically removed from the system.  But CPU-failure
> use cases would need the CPU to be fully deactivated.  And many of the
> hardware guys tell me that the CPU-failure case will be getting more
> common, though I sure hope that they are wrong.

Uhm, yeah, that doesn't sound right.


  reply	other threads:[~2012-06-06 12:17 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-04 18:17 [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi Fenghua Yu
2012-06-04 18:17 ` [PATCH 1/6] x86/Documentation/kernel-parameters.txt: Add wakeup_cpu_via_init kernel parameter help Fenghua Yu
2012-06-04 18:17 ` [PATCH 2/6] x86/head_32.S/head_64.S: Kernel entry code after waking up offline CPU via mwait or nmi Fenghua Yu
2012-06-04 18:17 ` [PATCH 3/6] x86/smpboot.c: Wake " Fenghua Yu
2012-06-04 18:58   ` Suresh Siddha
2012-06-04 19:35     ` Yu, Fenghua
2012-06-04 18:17 ` [PATCH 4/6] x86/apic_flat_64.c: Wakeup function in apic calls mwait or nmi method Fenghua Yu
2012-06-04 18:17 ` [PATCH 5/6] x86/x2apic_cluster.c: Wakeup function in x2apic_cluster " Fenghua Yu
2012-06-04 18:17 ` [PATCH 6/6] x86/x2apic_phys.c: Wakeup function in x2apic_phys " Fenghua Yu
2012-06-04 18:17 ` Fenghua Yu
2012-06-04 20:11 ` [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi Thomas Gleixner
2012-06-04 20:18   ` Luck, Tony
2012-06-04 22:52     ` Thomas Gleixner
2012-06-04 20:33   ` Peter Zijlstra
2012-06-05  0:40     ` Rusty Russell
2012-06-05  1:23       ` Arjan van de Ven
2012-06-05  7:38         ` Peter Zijlstra
2012-06-05 14:17         ` Alan Stern
2012-06-05 15:27           ` Arjan van de Ven
2012-06-05  7:39       ` Peter Zijlstra
2012-06-05 16:02         ` Yu, Fenghua
2012-06-05 16:09           ` Peter Zijlstra
2012-06-05 16:18             ` Yu, Fenghua
2012-06-05 16:19               ` Peter Zijlstra
2012-06-05 17:44                 ` Luck, Tony
2012-06-05 17:50                   ` Peter Zijlstra
2012-06-05 19:43                     ` Thomas Gleixner
2012-06-05 19:45                       ` Peter Zijlstra
2012-06-05 19:49                       ` Peter Zijlstra
2012-06-05 19:51                         ` Arjan van de Ven
2012-06-05 19:52                           ` Peter Zijlstra
2012-06-05 20:47                         ` Thomas Gleixner
2012-06-05 21:30                           ` Peter Zijlstra
2012-06-05 22:09                             ` Thomas Gleixner
2012-06-06  8:23                               ` Peter Zijlstra
2012-06-06  8:30                               ` Peter Zijlstra
2012-06-06  8:40                               ` Peter Zijlstra
2012-06-05 22:12                             ` Paul E. McKenney
2012-06-06  8:40                               ` Peter Zijlstra
2012-06-06  8:42                               ` Peter Zijlstra
2012-06-06 14:44                                 ` Paul E. McKenney
2012-06-06 15:46                                   ` Peter Zijlstra
2012-06-06 23:20                                     ` Paul E. McKenney
2012-06-08  9:20                                       ` Peter Zijlstra
2012-06-06  8:43                               ` Peter Zijlstra
2012-06-06 14:41                                 ` Paul E. McKenney
2012-06-06 15:23                                   ` Arjan van de Ven
2012-06-06 15:48                                     ` Peter Zijlstra
2012-06-06 15:49                                     ` Paul E. McKenney
2012-06-06 16:59                                       ` Arjan van de Ven
2012-06-05 21:29                         ` Paul E. McKenney
2012-06-05 21:37                           ` Peter Zijlstra
2012-06-05 22:00                             ` Paul E. McKenney
2012-06-06 12:17                               ` Peter Zijlstra [this message]
2012-06-06 14:43                                 ` Paul E. McKenney
2012-06-05 19:51                       ` Peter Zijlstra
2012-06-05 20:58                       ` Andi Kleen
2012-06-05 21:15                         ` Thomas Gleixner
2012-06-05 21:33                           ` Thomas Gleixner
2012-06-05 23:13                             ` Andi Kleen
2012-06-06  1:52                               ` Arjan van de Ven
2012-06-05 18:07                   ` Peter Zijlstra
2012-06-05 19:54                     ` Luck, Tony
2012-06-05 19:56                       ` Peter Zijlstra
2012-06-05  9:36       ` Thomas Gleixner
2012-06-05 13:41         ` [PATCH] kthread: Implement park/unpark facility Thomas Gleixner
2012-06-05 14:01           ` Peter Zijlstra
2012-06-05 14:05           ` Peter Zijlstra
2012-06-07  0:04             ` H. Peter Anvin
2012-06-10  5:40           ` Rusty Russell
2012-06-11  9:26             ` Thomas Gleixner
2012-06-12  0:23               ` Rusty Russell
2012-06-05 15:35   ` [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi Jiang Liu

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