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Date: Thu, 18 Jun 2015 16:25:17 +0200
From: Imre Palik <imrep.amz@gmail.com>
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To: Peter Zijlstra <peterz@infradead.org>
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
References: <1434378152-4042-1-git-send-email-imrep.amz@gmail.com> <20150616092136.GL3644@twins.programming.kicks-ass.net>
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On 06/16/15 11:21, Peter Zijlstra wrote:
> 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.
> 

I made the mistake of sending two different versions as v2.  v3 is the same
as the second v2.

I sent this to clear up possible confusion.  Sorry if it caused more of it.