PSU Energy - DC - RAPL Machine

What it does #

This metric provider reads the energy of the Platform (PSYS) domain from the Running Average Power Limit (RAPL) interface via a machine specific register (MSR) that is present on some Intel processor based notebook devices. In depth information about RAPL can be found here.

This MSR keeps a running count of the energy used in a specified domain in microJoules. This metric provider specifically reads from the energy-psys domain, which gives you the energy used by potentially the whole machine. The exact implementation what exactly falls under the PSYS domain is up to the manufacturer of the machine and in doubt you should contact the manufacturer.

We have tested this domain on modern Framework notebooks and the domain includes here at least all of the CPU, DRAM as well as the display.

System Setup #

On kernels > 2.6 all the kernel modules should automatically be loaded.

However just in case run:

sudo modprobe intel_rapl_common # or intel_rapl for kernels < 5
sudo modprobe intel_rapl_msr
sudo modprobe rapl

Technical specs #

• Time resolution: 976 micro-seconds
• Energy resolution: 15.3 micro-Joules

Classname #

• PsuEnergyDcRaplMsrMachineProvider

Metric Name #

• psu_energy_dc_rapl_msr_machine

Input Parameters #

• Args:
  • i: specifies interval in milliseconds between measurements

./metric-provider-binary -i 100

Output #

This metric provider prints to Stdout a continuous stream of data. The format of the data is as follows:

TIMESTAMP ENERGY_OUTPUT

Where:

• TIMESTAMP: Unix timestamp, in microseconds
• ENERGY_OUTPUT: Energy used during interval, in micro Joules
• PSYS_ID: ID of the PSYS domain. Actually this should always be PSYS_0, since we have never seen a device with more then one domain or more than one CPU chip (which also creates multiple domains in case), so we could not verify. If you experience inconsistencies here contact us please.

Example output:

1712641603443421 8092 PSYS_0
1712641604443831 8047 PSYS_0

Any errors are printed to Stderr.

How it works #

We use a modified version of the open source code found here: (github)

First we check if the CPU is compatible by reading the cpu info from /proc/cpuinfo and checking against the following list of supported CPUs:

CPU_SANDYBRIDGE, CPU_SANDYBRIDGE_EP, CPU_IVYBRIDGE, CPU_IVYBRIDGE_EP, CPU_HASWELL, CPU_HASWELL_ULT, CPU_HASWELL_GT3E, CPU_HASWELL_EP, CPU_BROADWELL, CPU_BROADWELL_GT3E, CPU_BROADWELL_EP, CPU_BROADWELL_DE, CPU_SKYLAKE, CPU_SKYLAKE_HS, CPU_SKYLAKE_X, CPU_KNIGHTS_LANDING, CPU_KNIGHTS_MILL, CPU_KABYLAKE_MOBILE, CPU_KABYLAKE, CPU_ATOM_SILVERMONT, CPU_ATOM_AIRMONT, CPU_ATOM_MERRIFIELD, CPU_ATOM_MOOREFIELD, CPU_ATOM_GOLDMONT, CPU_ATOM_GEMINI_LAKE, CPU_TIGER_LAKE

It reads the values from /dev/cpu/%d/msr

Note that since it reads the energy used by the entire system, any other load that your system has during a program’s usage run will also be captured in the energy measurement.