On Mon, Oct 7, 2013 at 6:19 PM, Borislav Petkov <b...@alien8.de> wrote: > 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? > We could but that means we would need to special case the events in perf. I was trying to avoid that.
> Thanks. > > -- > Regards/Gruss, > Boris. > > Sent from a fat crate under my desk. Formatting is fine. > -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
