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
next prev parent 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 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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