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Date: Tue, 16 Jun 2015 11:21:36 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Imre Palik <imrep.amz@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        x86@kernel.org, linux-kernel@vger.kernel.org,
        "Palik, Imre" <imrep@amazon.de>, Anthony Liguori <aliguori@amazon.com>
Subject: Re: [PATCH v3] perf: honoring the architectural performance
 monitoring version
Message-ID: <20150616092136.GL3644@twins.programming.kicks-ass.net>
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On Mon, Jun 15, 2015 at 04:22:32PM +0200, Imre Palik wrote:
> From: "Palik, Imre" <imrep@amazon.de>
> 
> Architectural performance monitoring version 1 doesn't support fixed
> counters.  Currently, even if a hypervisor advertises support for
> architectural performance monitoring version 1, perf may still tries to use
> the fixed counters, as the constraints are set up based on the CPU model.
> 
> This patch ensures that perf honors the architectural performance
> monitoring version returned by CPUID, and it only uses the fixed counters
> for version two and above.
> 
> Some of the ideas in this patch are coming from Peter Zijlstra.

What's the difference from -v2? I'm not really seeing it.