This page presents how you can build a power meter with the tools provided by PowerAPI. We present the different components of a power meter and how you can connect them to build a workflow for your own needs.

A power meter is an application build with the PowerAPI components that can measure the power consumption of software running on a single machine or on a cluster of machine.

This section present each PowerAPI component type and how connect them to build a power meter.

Power meter Architecture

A power meter is a set of two components, a sensor and a formula, used to produce an estimation of the power consumption of a monitored software.

The sensor collects raw data correlated with the power consumption of the software. The formula is a model that use the collected data to compute the power consumption. Both of them are connected by a database that is used to transfer data from the sensor to the formula.

The two next sub-sections present how a sensor and a formula work and how they should be used.

arch

Sensor

A sensor is an independent software that collects raw data correlated with the power consumption of monitored software.

Data are collected by querying the hardware’s machine that hosts the monitored software. The sensor must be executed on the same machine as the monitored software. The data are collected throughout the duration of the software. For this reason, the sensor must operate in parallel.

Collected data are stored in an external database to make the data available to the formula. This database may be hosted on an other machine.

Usage

Because they collect from different hardware, each sensor are very different from one another. Refer to each sensor documentation to know how to use them.

Formula

A formula is an independent software that use model to compute the power consumption of monitored software from the data collected by the sensor.

Sensor Connection

A formula is connected to a sensor via a database (e.g MongoDB). The sensor writes the collected data to the database and the formula reads this data from the database.

There are two connection modes:

  • “Stream” mode where data is read from the database while the sensor is collecting it

  • “Post-mortem” mode which analyses the data already collected by the sensor in a past monitoring phase.