#### Design of Sustainable Systems

##### Advisor *Joël Goossens*

###### Keywords *embedded, OS, design*

### Introduction

The main topic is related to **Sustainable (Green) IT**. The main goal is to reduce the impact of the IT to the environment. This is a hot topic nowadays in both industrial and research fields. For instance, this is a major concern of data centers for which the energy bill increases considerably. Recent research estimates that IT represents about 10% of the world’s electricity (30% for end-user equipment, 30% for data centers, 40% for the network). Along with the energy efficiency of buildings and vehicles, it is therefore also necessary to improve the energy efficiency of IT. The financial and ecological stakes of sustainable IT are therefore very important. For example, the objective of a 50% reduction in electricity consumption would correspond to the non-emission of 7 million tons of CO2 in 3 years (or expected savings of around $5.5 billion). In the same vein sustainable IT is in phase with the Paris agreement (COP21) which sets out a global framework to avoid dangerous climate change by limiting global warming to well below 2°C and pursuing efforts to limit it to 1.5°C.

**Several** master thesis sub-topics are available, please contact joel.goossens@ulb.be if your are interested

### Sub-topics

- Software engineering process for sustainable systems
- Sustainable operating systems
- Sustainable embedded systems (hardware, middleware aspects in collaboration with Prof.Dragomir Milojevic)
- Energy efficient network (in collaboration with Prof. Jean-Michel Dricot)

#### Template schedule heuristics for real-time workload and unrelated multiprocessors

##### Advisor *Joël Goossens*

###### Keywords *RTOS, scheduling*

### Introduction

Heterogeneous MPSoCs are being used more and more, from cellphones to critical embedded systems. Most of those systems offer heterogeneous sets of identical cores. Very often the scheduling method of the literature (see below), starts with a workload assignment phase. From an input made of tasks parameters and platform rates, this phase decides the *fraction* of processing capacity of each core assigned to tasks. This workload assignment phase is then followed by the construction of a *template schedule*. This template schedule contains a feasible schedule of the periodic task set (over a time instant).

### The thesis content

The student will study the literature about real-time scheduling upon heterogeneous platforms and contribute to the definition of good heuristics for the template schedule in particular.

### References

Sanjoy K. Baruah. 2004. Feasibility Analysis of Preemptive Real-Time Systemsupon Heterogeneous Multiprocessor Platforms. In IEEE Real-Time Systems Symposium., 37–46.

Eugene L. Lawler and Jacques Labetoulle. 1978. On Preemptive Scheduling of Unrelated Parallel Processors by Linear Programming. JACM 25, 4 (1978), 612–619.

#### Scheduling of multi-phase tasks upon unrelated multiprocessor

##### Advisor *Joël Goossens*

###### Keywords *RTOS, scheduling*

### Introduction

Heterogeneous MPSoCs are being used more and more, from cellphones to critical embedded systems. Most of those systems offer heterogeneous sets of identical cores. A multi-phase task is composed of a *sequence* of phases, each phase is characterised by its duration and processor affinity.

### The thesis content

The student will study the literature related to scheduling on unrelated platforms and contribute to the definition of a solution for the scheduling of *multi-phase* real-time tasks

### References

- Sanjoy K. Baruah and Björn Brandenburg. Multiprocessor feasibility analysis of recurrent task systems with specified processor affinities. In IEEE Real-Time Systems Symposium, pages 160–169. Dec 2013.
- Bertout, A., Goossens, J., Grolleau, E., and Poczekajlo, X. Template schedule construction for global real-time scheduling on unrelated multiprocessor platforms. Proceedings - Design, Automation, and Test in Europe Conference and Exhibition. March 2020.

#### Study of the COQ Proof Assistant, application to Real-time scheduling

##### Advisor *Joël Goossens*

###### Keywords *RTOS, scheduling, Automatic proof*

### Description

Coq is a formal proof management system. It provides a formal language to write mathematical definitions, executable algorithms and theorems together with an environment for semi-interactive development of machine-checked proofs. Typical applications include the certification of properties of programming languages (e.g. the CompCert compiler certification project, or the Bedrock verified low-level programming library), the formalization of mathematics (e.g. the full formalization of the Feit-Thompson theorem or homotopy type theory) and teaching. Citation https://coq.inria.fr/

The student will study the COQ tool and language. Then the student will illustrate how to use that tool in the framework real-time scheduling properties using example based upon real-time literature.