Looking for something specific? Use our search engine!

Press Release

Press Release

Doctoral Thesis on Energy Aware Run Time Systems for Elastic Stream Processing Platforms


Hergys Rexha.
Hergys Rexha

M.Sc. Hergys Rexha’s doctoral thesis in Computer Engineering will be put forth for public defence at the Faculty of Science and Engineering at Åbo Akademi University.

The thesis is entitled Energy Aware Run Time Systems for Elastic Stream Processing Platforms.

The public defence of the doctoral thesis takes place on 22 August 2023 at 1PM in auditorium XX, Agora, Vesilinnantie 3, Turku. Professor Jean-Marc Pierson, University of Toulouse, France will serve as opponent and Docent Sébastien Lafond, Åbo Akademi University, as custos.


Following an invariant growth in the required computational performance of processors, the multicore revolution started around 20 years ago. The multicore revolution not only brought in the challenge of parallel programming, i.e., being able to develop software exploiting the entire capabilities of many- core architectures, but also the challenge of programming heterogeneous platforms.

The question of “on which processing element to map a specific computational unit?”, is well known in the embedded community. With the introduction of general-purpose graphics processing units (GPGPUs), digital signal processors (DSPs) along with many-core processors on different system-on-chip platforms, heterogeneous parallel platforms are nowadays widespread over several domains, from consumer devices to media processing platforms for telecom operators. Finding mapping together with a suitable hardware architecture is a process called design-space exploration. This
process is very challenging in heterogeneous many-core architectures, which promise to offer benefits in terms of energy efficiency.

The main problem is the exponential explosion of space exploration. With the recent trend of increasing levels of heterogeneity in the chip, selecting the parameters to take into account when mapping software to hardware is still an open research topic in the embedded area. For example, the current Linux scheduler has poor performance when mapping tasks to computing elements, the only metric considered is CPU workload which as was shown does not match true performance demands from the applications. Doing so may produce an incorrect allocation of resources, resulting in a waste of energy.

The origin of this research work comes from the observation that these approaches do not provide full support for the dynamic behavior of stream processing applications, especially if these behaviors are established only at runtime. This research will contribute to the general goal of developing energy-efficient solutions to design streaming applications on heterogeneous and parallel hardware platforms. Streaming applications are nowadays widely spread in the software domain. Their distinctive characteristic is the retrieving of multiple streams of data and the need to process them in real time.

The proposed work will develop new approaches to address the challenging problem of efficient runtime coordination of dynamic applications, focusing on energy and performance management.


Hergys Rexha was born in 1984 in Tirana, Albania. He can be reached by phone +358 46 560 4248 or email hergys.rexha@abo.fi.


The doctoral thesis can be read online through the Doria publication archive.

Click here for a press photo of the doctoral student.