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From: Andi Kleen <andi@firstfloor.org>
To: Lin Ming <ming.m.lin@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>,
	Stephane Eranian <eranian@google.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/6] perf: Optimise topology iteration
Date: Mon, 21 Feb 2011 04:32:35 +0100	[thread overview]
Message-ID: <20110221033235.GW5818@one.firstfloor.org> (raw)
In-Reply-To: <1298258964.17806.48.camel@minggr.sh.intel.com>

On Mon, Feb 21, 2011 at 11:29:24AM +0800, Lin Ming wrote:
> On Mon, 2011-02-21 at 05:15 +0800, Andi Kleen wrote:
> > On Mon, Feb 21, 2011 at 12:57:39AM +0800, Lin Ming wrote:
> > > Currently we iterate the full machine looking for a matching core_id/nb
> > > for the percore and the amd northbridge stuff , using a smaller topology
> > > mask makes sense.
> > 
> > This is still wrong for CPU hotplug. The CPU "owning" the per core
> > does not necessarily need to be online anymore.
> 
> This is remain issue for hotplug case, no matter we use
> for_each_online_cpu or topology_thread_cpumask.

The original code I submitted used for_each_possible_cpu which
is correct.

> 
> > Please drop this patch.
> 
> Re-look at the code, I think for_each_online_cpu is wrong for percore,
> we should use topology_thread_cpumask instead.

No, that's also cleared on unplug. You really need the possible map
and nothing else.

-Andi

  reply	other threads:[~2011-02-21  3:32 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-20 16:57 Lin Ming
2011-02-20 21:15 ` Andi Kleen
2011-02-21  3:29   ` Lin Ming
2011-02-21  3:32     ` Andi Kleen [this message]
2011-02-21  5:01       ` Lin Ming

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