Subject: Re: [patch] Performance Counters for Linux, v3
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: eranian@gmail.com
Cc: Vince Weaver <vince@deater.net>, Ingo Molnar <mingo@elte.hu>,
       linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
       Andrew Morton <akpm@linux-foundation.org>,
       Eric Dumazet <dada1@cosmosbay.com>,
       Robert Richter <robert.richter@amd.com>,
       Arjan van de Veen <arjan@infradead.org>, Peter Anvin <hpa@zytor.com>,
       Paul Mackerras <paulus@samba.org>,
       "David S. Miller" <davem@davemloft.net>
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Date: Sat, 13 Dec 2008 12:17:28 +0100
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On Fri, 2008-12-12 at 18:42 +0100, stephane eranian wrote:
> In fact, I know tools which do not even need a library. 

By your own saying, the problem solved by libperfmon is a hard problem
(and I fully understand that).

Now you say there is software out there that doesn't use libperfmon,
that means they'll have to duplicate that functionality.

And only commercial software has a clear gain by wastefully duplicating
that effort. This means there is an active commercial interest to not
make perfmon the best technical solution there is, which is contrary to
the very thing Linux is about.

What is worse, you defend that:

> Go ask end-users what they think of that?
> 
> You don't even need a library. All of this could be integrated into the tool.
> New processor, just go download the updated version of the tool.

No! what people want is their problem fixed - no matter how. That is one
of the powers of FOSS, you can fix your problems in any way suitable.

Would it not be much better if those folks duped into using a binary
only product only had to upgrade their FOSS kernel, instead of possibly
forking over more $$$ for an upgrade?

You have just irrevocably proven to me this needs to go into the kernel,
as the design of perfmon is little more than a GPL circumvention device
- independent of whether you are aware of that or not.

For that I hereby fully NAK perfmon

Nacked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>


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