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| Started by | Jacob Pan <jacob.jun.pan@linux.intel.com> |
|---|---|
| First post | 2015-06-15 22:10 +0200 |
| Last post | 2015-06-15 22:10 +0200 |
| Articles | 1 — 1 participant |
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Re: [PATCH v3] perf/rapl: support per domain energy unit Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-06-15 22:10 +0200
| From | Jacob Pan <jacob.jun.pan@linux.intel.com> |
|---|---|
| Date | 2015-06-15 22:10 +0200 |
| Subject | Re: [PATCH v3] perf/rapl: support per domain energy unit |
| Message-ID | <pBIRI-5m8-1@gated-at.bofh.it> |
On Mon, 15 Jun 2015 13:32:01 -0400 (EDT) Vince Weaver <vincent.weaver@maine.edu> wrote: > On Thu, 26 Mar 2015, Jacob Pan wrote: > > > RAPL energy hardware unit can vary within a single CPU package, e.g. > > HSW server DRAM has a fixed energy unit of 15.3 uJ (2^-16) whereas > > the unit on other domains can be enumerated from power unit MSR. > > There might be other variations in the future, this patch adds > > per cpu model quirk to allow special handling of certain cpus. > > So I have a Desktop Haswell machine (model 60) that is instrumented > to measure actual DRAM power at the DIMM (with a sense resistor). > > We are consistently getting RAPL results roughly a factor of 2 > smaller than the actual, measured results. > > Does desktop Haswell have a similar units issue to Haswell-EP? > Not that I know of. perhaps has to do with the difference of what and where we are measuring. Let me find a instrumented system to verify and get back to you. > I wasted a bunch of time trying to decode the > DRAM_ENERGY_SCALEFACTOR_MCHBAR values described in the > Desktop 4th Generation Intel Core Processor Family > datasheet but possibly that value in the MCHBAR is unrelated to the > one exported by the RAPL interface. > This scale factor is not directly related to the energy counter. The MMIO DRAM RAPL energy status uses the same unit as the MSR interface, the resolution is ~61uJ. > Vince [Jacob Pan] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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