GEMSCLAIM: GreenEr Mobile Systems by Cross LAyer Integrated energy Management

Personal computing currently faces a rapid trend from desktop machines towards mobile services, accessed via tablets, smartphones and similar terminal devices. With respect to computing power, today 's handheld devices are similar to Cray-2 supercomputers from the 1980s. Due to higher computational load (e.g. via multimedia apps) and the variety of radio interfaces (such as WiFi, 3G, and LTE), modern terminals are getting increasingly energy hungry. For instance, a single UMTS upload or a video recording process on today 's smartphones may consume as much as 1.5 Watts, i.e. roughly 50% of the maximal device power. In the near future, higher data rates and traffic, advanced media codecs, and graphics applications will ask for even more energy than the battery can deliver. At the same time, the power density limit might lead to a significant share of "Dark Silicon" at 22nm CMOS and below. Obviously, disruptive energy optimizations are required that go well beyond traditional technologies like DVFS (dynamic voltage and frequency scaling) and power-down of temporarily unused components. The GEMSCLAIM project aims at introducing novel approaches for reducing this "greed for energy", thereby improving the user experience and enabling new opportunities for mobile computing. The focus is on three novel approaches: (1) cross layer energy optimization, ranging from the compiler over the operating system down to the target HW platform, (2) efficient programming support for energy-optimized heterogeneous Multicore platforms based on energy-aware service level agreements (SLAs) and energy-sensitive tunable parameters, and (3) introducing energy awareness into Virtual Platforms for the purpose of dynamically customizing the HW architecture for energy optimization and online energy monitoring and accounting. GEMSCLAIM will provide new methodologies and tools in these domains and will quantify the potential energy savings via benchmarks and a HW platform prototype.

GEMSCLAIM aims at a paradigm shift from throughput-oriented to energy-oriented parallel computing. The performance of computing systems is already defined by the available power, yet most layers of the HW/SW stack of modern systems are optimized without power considerations. GEMSCLAIM will develop methods and tools for energy-aware optimization throughout the HW and SW stack.

Parallel programming already faces major challenges in dealing with the increasing diversity and heterogeneity of parallel architectures. These challenges will only grow larger as energy will become the main limitation in future architectures. GEMSCLAIM involves the programmer in energy management, through OpenMP+ directives that assist in energy conservation by parallel programs. At the same time, GEMSCLAIM implements a high-productivity parallel programming environment based on OpenMP+, which effectively supports heterogeneous Multicore platforms.

GEMSCLAIM makes energy a first-class citizen in computing systems, by developing a HW/SW environment that manages energy as a resource that is equally critical as other resources, such as processor time and memory space. GEMSCLAIM also advocates a fundamental departure from the current fragmented models of energy management in computing systems. The GEMSCLAIM HW/SW environment develops holistic energy optimization by controlling a multitude of tunable HW and SW parameters and leveraging dynamic workload properties.

All partners of GEMSCLAIM are active and prolific members of the HiPEAC European Network of Excellence. One of the project's principal investigators is also a contributor of the 2012 HiPEAC Roadmap (http://www.hipeac.net/system/files/hipeac-roadmap2011.pdf). GEMSCLAIM responds to the two major future challenges identified by the HiPEAC Roadmap: Efficiency, "measured as the amount of computation that we can accomplish per unit of energy" and Complexity "which identifies the need to provide tools and techniques for enabling developers of SW and new HW to leverage increasingly complex systems for increasingly complex applications". GEMSCLAIM also responds to the societal challenges of environmental protection and productivity: Computing systems are a part of the growing energy problem, consuming hundreds of Gigajoules of energy annually (about as much as civil aviation). Computing systems are also an essential ingredient of productivity in all aspects of human economic activity.

For the successful dissemination of the GEMSCLAIM's scientific and technical outcomes, dissemination activities run in parallel with project management coordinating the various activities concerned with successive knowledge transfer. Disseminating GEMSCLAIM achievements is an integral part of all work-packages and a responsibility for all participants. Integrity and consistency of all dissemination efforts are to be supervised in WP1.

The strategy will aim at getting in touch with target audience with recognizable, clear and effective messages able to communicate project vision and achievements as well as to stimulate the interest in project technology and objectives. The specific objectives of the strategy are the
- share scientific results with the international community
- increase awareness of scientific and technological benefits of the targeted results
- inform potential users of project achievements and prepare the way for exploitation
- establish scientific and business relationships with institutions and companies involved in the same technological domain or potential users of the project outcomes
- spread results within established networks, e.g. through workshops, concertation events.