# Measurement methods sheet, WG6 Exa-Soft

Georges da Costa, Amina Guermouche

► To cite this version:

Georges da Costa, Amina Guermouche. Measurement methods sheet, WG6 Exa-Soft. Université de Toulouse; Université de Bordeaux. 2025. hal-05272179

HAL Id: hal-05272179

https://hal.science/hal-05272179v1

Submitted on 22 Sep 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
# Measurement methods sheet, WG6 Exa-Soft

## Energy and Power

$$Energy(J) = Power(W) * Time(s)$$

Classical use

* If $t[i]$ is the series of power every 1/10s then

$$E = \sum \left( \frac{t[i]}{10} \right)$$

## Classical models

* Server: Power = Static + Σ/components

* CPU: Power α Load

* RAM

* Storage/Network: Power ≅ Constant

## Leverages

* DVFS (Dynamic Voltage and Frequency Scaling) : decreasing frequencies (CPU or GPU or RAM) increases times and reduces power

* PowerCap : bounds the maximum power of a subsystem

## Pitfalls

### Heterogeneity of hardware

Homogeneous servers consume differently. Here same servers, idles, one measure per second during 5 minutes.

<figure><img src="image_2.png" /></figure>

### Heterogeneity of software

Different applications consume different power and react differently to leverages (here DVFS)

<figure><img src="image_3.png" /></figure>

## Measure

* IPMI or BMC : classically used for protection against electrical problem at server or rack level

* Low precision / frequency / reactivity

* e-Pdu : outlet level, usually one per server

* Medium precision, frequency up to 1Hz

* RAPL (or equivalent) : power measure (and model) inside the CPU/RAM/GPU

* High precision, frequency up to 1kHz, can go down to each core

<figure><img src="image_4.png" /></figure>

### Stability of measures

100 experiments, same 4 servers, same application

<figure><img src="image_5.png" /></figure>

### Some pointers

* CPU/RAM/GPU-level measure : MojitO/S

* Process-level measure : PowerAPI

* DC-level measure : EZTrace

RQ: need specific configuration (or root access)

* Tools Comparison:
  10.1109/CCGrid57682.2023.00020

* Methodology of measure :
  10.1016/j.suscom.2017.05.003

* Models (CPU+DVFS) :
  10.1016/j.suscom.2025.101106