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Date: Mon, 7 Nov 2011 22:09:34 +0200 (EET)
From: Pekka Enberg <penberg@cs.helsinki.fi>
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To: "Frank Ch. Eigler" <fche@redhat.com>
cc: Ingo Molnar <mingo@elte.hu>, Vince Weaver <vince@deater.net>,
        "Ted Ts'o" <tytso@mit.edu>, Pekka Enberg <penberg@kernel.org>,
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        Peter Zijlstra <a.p.zijlstra@chello.nl>,
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Subject: Re: [Qemu-devel] [PATCH] KVM: Add wrapper script around QEMU to test
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On Mon, 7 Nov 2011, Frank Ch. Eigler wrote:
>> The ABI design allows for that kind of flexible extensibility, and
>> it's one of its major advantages.
>>
>> What we *cannot* protect against is you relying on obscure details of
>> the ABI [...]
>
> Is there some documentation that clearly spells out which parts of the
> perf syscall userspace ABI are "obscure" and thus presumably
> changeable?

That's actually something the KVM and virtio folks have done a great job 
with IMHO. Both ABIs are documented pretty extensively and the specs are 
kept up to date.

I guess for perf ABI, "perf test" is the closest thing to a specification 
so if your application is using something that's not covered by it, you 
might be in trouble.

 			Pekka