linux-kernel - Re: [PATCH v1 0/2] perf,x86: add Intel RAPL PMU support

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Message-ID: <20131007161928.GC5517@pd.tnic>
Date:	Mon, 7 Oct 2013 18:19:29 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	linux-kernel@...r.kernel.org, peterz@...radead.org, mingo@...e.hu,
	ak@...ux.intel.com, acme@...hat.com, jolsa@...hat.com,
	zheng.z.yan@...el.com
Subject: Re: [PATCH v1 0/2] perf,x86: add Intel RAPL PMU support

On Mon, Oct 07, 2013 at 06:09:15PM +0200, Stephane Eranian wrote:
> The counters all count in the same unit. The perf_events API
> exposes all RAPL counters as 64-bit integers counting in unit
> of 1/2^32 Joules (or 0.23 nJ). User level tools must convert
> the counts by multiplying them by 0.23 and divide 10^9 to
> obtain Joules.  The reason for this is that the kernel avoids
> doing floating point math whenever possible because it is
> expensive (user floating-point state must be saved). The method
> used avoids kernel floating-point and minimizes the loss of
> precision (bits). Thanks to PeterZ for suggesting this approach.
> 
> To convert the raw count in Watt: W = C * 0.23 / (1e9 * time)

...

> $ perf stat -a -e rapl/rapl-energy-cores/,rapl/rapl-energy-pkg/ -I 1000 sleep 10
>             time             counts events
>      1.000345931        772 278 493 rapl/rapl-energy-cores/
>      1.000345931     55 539 138 560 rapl/rapl-energy-pkg/    
>      2.000836387        771 751 936 rapl/rapl-energy-cores/  
>      2.000836387     55 326 015 488 rapl/rapl-energy-pkg/

So can we do the Watt conversion in perf tool and make that "counts"
output more human-friendly like what those numbers are, to which
core/LLC they belong, etc, etc?

Thanks.

-- 
Regards/Gruss,
    Boris.

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