linux-kernel - Re: [tip:perf/core] perf/x86/intel: Add {rd,wr}lbr

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Message-ID: <20160629193244.GZ30921@twins.programming.kicks-ass.net>
Date:	Wed, 29 Jun 2016 21:32:44 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	linux-kernel@...r.kernel.org, tglx@...utronix.de, acme@...hat.com,
	mingo@...nel.org, jolsa@...hat.com, vincent.weaver@...ne.edu,
	eranian@...gle.com, alexander.shishkin@...ux.intel.com,
	hpa@...or.com, kan.liang@...el.com, torvalds@...ux-foundation.org,
	davidcc@...gle.com
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:perf/core] perf/x86/intel: Add {rd,wr}lbr_{to,from} wrappers

On Mon, Jun 27, 2016 at 05:56:02AM -0700, tip-bot for Peter Zijlstra wrote:
> +static inline u64 rdlbr_from(unsigned int idx)
> +{
> +	u64 val;
> +
> +	rdmsrl(x86_pmu.lbr_from + idx, val);
> +
> +	return lbr_from_signext_quirk_rd(val);
> +}
> +
> +static inline u64 rdlbr_to(unsigned int idx)
> +{
> +	u64 val;
> +
> +	rdmsrl(x86_pmu.lbr_from + idx, val);

Things work loads better when we use:

	rdmsrl(x86_pmu.lbr_to + idx, val);

:-/

> +
>  	return val;
>  }