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From: Andi Kleen <ak@linux.intel.com>
To: Imre Palik <imrep.amz@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
	Stephane Eranian <eranian@google.com>,
	Kan Liang <kan.liang@intel.com>,
	David Carrillo-Cisneros <davidcc@google.com>,
	linux-kernel@vger.kernel.org,
	Alexander Kozyrev <alexander.kozyrev@intel.com>,
	Artyom Kuanbekov <artyom.kuanbekov@intel.com>,
	Imre Palik <imrep@amazon.de>, Matt Wilson <msw@amazon.com>,
	David Woodhouse <dwmw@amazon.co.uk>
Subject: Re: [RFC PATCH v2] perf: honouring the cpuid for number of fixed counters in hypervisors
Date: Mon, 24 Oct 2016 09:50:00 -0700	[thread overview]
Message-ID: <20161024165000.GF1075@tassilo.jf.intel.com> (raw)
In-Reply-To: <1477037939-15605-1-git-send-email-imrep.amz@gmail.com>

On Fri, Oct 21, 2016 at 01:18:59AM -0700, Imre Palik wrote:
> From: Imre Palik <imrep@amazon.de>
> 
> perf doesn't seem to honour the number of fixed counters specified by cpuid
> leaf 0xa.  It always assume that Intel CPUs have at least 3 fixed counters.
> 
> So if some of the fixed counters are masked out by the hypervisor, it still
> tries to check/set them.
> 
> This patch makes perf behave nicer when the kernel is running under a
> hypervisor that doesn't expose all the counters.
> 
> This patch contains some ideas from Matt Wilson.

Patch looks good to me.

Reviewed-by: Andi Kleen <ak@linux.intel.com>

-Andi

  reply	other threads:[~2016-10-24 16:50 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-21  8:18 [RFC PATCH v2] perf: honouring the cpuid for number of fixed counters in hypervisors Imre Palik
2016-10-24 16:50 ` Andi Kleen [this message]
2016-10-26  9:16 ` Peter Zijlstra
2016-10-28 10:11 ` [tip:perf/urgent] perf/x86/intel: Honour the CPUID " tip-bot for Imre Palik

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