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Date: Tue, 3 Apr 2007 19:30:10 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ulrich Drepper <drepper@redhat.com>, Andi Kleen <andi@firstfloor.org>,
       Linux Kernel <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: getting processor numbers
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References: <461286D6.2040407@redhat.com> <p73abxpz5u1.fsf@bingen.suse.de> <46128C1B.1090900@redhat.com> <20070403182241.4b9abab6@the-village.bc.nu>
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On Tue, Apr 03, 2007 at 06:22:41PM +0100, Alan Cox wrote:
> > benefit for the common use cases.  But as it is, the number of
> > processors is not necessarily constant over the lifetime of a process.
> > The machine architecture is.
> 
> Not once you have migration capable virtualisation it isnt.

Migration is fundamentally incompatible with many CPU optimizations.
But that's not a reason to not optimize anymore.

But I guess luckily most migration users will be able to live
with a little decreased performance after it.

-Andi