Date: Thu, 11 Jun 2009 19:58:37 -0700 (PDT)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
cc: Jiri Slaby <jirislaby@gmail.com>, Sam Ravnborg <sam@ravnborg.org>,
       Marcel Holtmann <marcel@holtmann.org>, Ingo Molnar <mingo@elte.hu>,
       Martin Bligh <mbligh@google.com>, Christoph Hellwig <hch@infradead.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       "David S. Miller" <davem@davemloft.net>,
       Stephane Eranian <eranian@googlemail.com>, linux-kernel@vger.kernel.org,
       Paul Mackerras <paulus@samba.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [GIT PULL] Performance Counters for Linux
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On Fri, 12 Jun 2009, Al Viro wrote:
> 
> So could you please clarify the situation?  If the ABI compatibility
> requirements remain the same as they used to be, whether the userland code
> is in-tree or not, I'm fine with the entire thing.  If they do not (and *ONLY*
> in that case), I think we have a real problem.

I think the ABI requirements are the same.

That said, I also suspect that as with oprofile itself, we'll end up 
having expansions of the ABI that may well be CPU-specific. I also suspect 
that there will probably be breakage early on just because things will 
inevitably settle. 

And I think that for something like a profiling tool, such breakage is 
much more acceptable than for the actual binaries you'd profile. It's not 
like we're talking about breaking the boot or functionality of a machine, 
as happens when we break the X server (which has happened).

		Linus
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