A major challenge in computing is to leverage multi-core technology to develop energy-efficient high performance systems. This is critical for embedded systems with a very limited energy budget as well as for supercomputers in terms of sustainability. Moreover the efficient programming of multi-core architectures, as we move towards manycores with more than a thousand cores predicted by 2020, remains an unresolved issue. The FlexTiles project will define and develop an energy-efficient yet programmable heterogeneous manycore platform with self-adaptive capabilities.
The manycore will be associated with an innovative virtualisation layer and a dedicated tool-flow to improve programming efficiency, reduce the impact on time to market and reduce the development cost by 20 to 50%.
FlexTiles will raise the accessibility of the manycore technology to industry – from small SMEs to large companies – thanks to its programming efficiency and its ability to adapt to the targeted domain using embedded reconfigurable technologies.
FlexTiles is a 3D stacked chip with a manycore layer and a reconfigurable layer. This heterogeneity brings a high level of flexibility in adapting the architecture to the targeted application domain for performance and energy efficiency.
A virtualisation layer on top of a kernel hides the heterogeneity and the complexity of the manycore and fine-tunes the mapping of an application at runtime. The virtualisation layer provides self-adaptation capabilities by dynamically relocation of application tasks to software on the manycore or to hardware on the reconfigurable area. This self-adaptation is used to optimise load balancing, power consumption, hot spots and resilience to faulty modules.
The reconfigurable technology is based on a virtual bitstream that allows dynamic relocation of accelerators just as software based on virtual binary code allows task relocation. This flexibility allows the use of fault mitigation schemes, a crucial issue for future manycores. During the execution of the application, the runtime binding is done to match the configuration defined by the virtualisation layer. It adapts the location of the code, the storage and the communication paths on the fly.
We will develop low-level monitoring and actuator functions to tune the workload of the tiles and their instantaneous power consumption.
Interconnection is a tremendous issue for using reconfigurable technologies with manycore. The solution proposed by the FlexTiles consortium focuses on the interfaces between the layers of the 3D stacked chip to ensure an efficient access to the reconfigurable layer by the manycore layer.
Parallelisation, mapping and code generation tools help the designers to implement their application in an optimal way on the heterogeneous manycore.
Demonstration and Use
The main result is the definition and development of a heterogeneous manycore with self adaptation capabilities, its virtualisation layer and its tool chain ensuring programming efficiency and low power consumption.
SystemC simulators and FPGA demonstrators will be delivered to demonstrate the capabilities of the manycore. Two use cases will be used for the evaluation of the results: (1) cognitive radio that shall be able to manage several radio frequency spectrums at low power consumption using the self adaptive capabilities of FlexTiles and (2) a smart camera data dependant application with low volume and low power consumption constraints that shall dynamically adapt its computing to the environment using the self adaptive capabilities. In both use cases, we will evaluate the development costs gained when using the tool flow.
Scientific, Economic and societal Impact
The proposed manycore with its self-adaptive capabilities is a technological breakthrough in complete adequation with the new applications needing dynamic adaptation and mode swapping at runtime. THALES and SUNDANCE end users will get a competitive advantage for their core markets like cognitive radio, video processing, embedded devices and ambient computing. European industry will benefit from the FlexTiles manycore because it will be like an ASIC dedicated to each application domain but with a high level of accessibility. The tremendous flexibility of the solution allows using a new business model where different customers are gathered around a common basis reducing in return the impact of the foundry cost. The project will improve the core products of Compaan, i.e. parallelisation and compilation tools, by extension to dynamic reconfigurable systems. The results of the FlexTiles project will be introduced in the educational programme of the academic partners.