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Date: Tue, 8 Nov 2011 12:34:16 +0100
From: Ingo Molnar <mingo@elte.hu>
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Subject: Re: [Qemu-devel] [F.A.Q.] perf ABI backwards and forwards
	compatibility
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To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Alexander Graf <agraf@suse.de>, Ted Ts'o <tytso@mit.edu>, Arnaldo Carvalho de Melo <acme@redhat.com>, "kvm@vger.kernel.org list" <kvm@vger.kernel.org>, qemu-devel Developers <qemu-devel@nongnu.org>, Vince Weaver <vince@deater.net>, "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>, Pekka Enberg <penberg@kernel.org>, Blue Swirl <blauwirbel@gmail.com>, "Frank Ch. Eigler" <fche@redhat.com>, Pekka Enberg <penberg@cs.helsinki.fi>, Avi Kivity <avi@redhat.com>, =?iso-8859-1?Q?Am=E9rico?= Wang <xiyou.wangcong@gmail.com>, Linus Torvalds <torvalds@linux-foundation.org>


* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> The ABI yes, the tool no, the tool very much relies on some newer 
> ABI parts. Supporting fallbacks isn't always possible/wanted.

Yeah, sure - and an older tool cannot possibly support newer features 
either.

Thanks,

	Ingo