linux-kernel - Re: [PATCH v7 3/4] perf,x86: add Intel RAPL PMU support

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Message-ID: <20131129203103.GJ4266@pd.tnic>
Date:	Fri, 29 Nov 2013 21:31:03 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	Vince Weaver <vince@...ter.net>, Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"mingo@...e.hu" <mingo@...e.hu>,
	"ak@...ux.intel.com" <ak@...ux.intel.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Jiri Olsa <jolsa@...hat.com>,
	"Yan, Zheng" <zheng.z.yan@...el.com>,
	Maria Dimakopoulou <maria.n.dimakopoulou@...il.com>
Subject: Re: [PATCH v7 3/4] perf,x86: add Intel RAPL PMU support

On Fri, Nov 29, 2013 at 09:09:46PM +0100, Stephane Eranian wrote:
> > So in theory it would be harmless to export the values even if not
> > supported.  What is the worst failure mode?  That somehow a recent CPU
> > doesn't support the MSR and we get a GPF when trying to access it?
> >
> Yes. I think that's what you get with DRAM on client for instance.

We have rdmsr_safe for non-existent MSRs, in case touching such is the
issue.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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