Team aoste

Overall Objectives
Scientific Foundations
Application Domains
New Results
Contracts and Grants with Industry
Other Grants and Activities

Section: New Results

AAA models

Participants : Liliana Cucu, Thierry Grandpierre, Patrick Meumeu, Nicolas Pernet, Mickaël Raulet, Yves Sorel.

We clearly stated the differences between our algorithm model and the typical model used by the real-time community in the monoprocessor case. We justified that ``release time'' and ``deadline'' are not necessary and that ``strict periodicity'' is sufficient, for applications using signal, image and control processing algorithms. Also, we justified that the ``latency'' constraints is more powerful than ``deadline'' in the sense that on the one hand two deadlines are necessary to impose a latency constraint, and on the other hand these two deadlines over-constraint the system of operations. We proposed a systematic method to transform a problem specified with latency model in a problem specified with deadlines more usual to the real-time community [57] . We proposed a new model to specify conditionings inside data-flow graph such that its implementation onto distributed architecture is effective, whereas this problem is often neglected leading to dramatic errors observed at run-time. This model was successfully used to develop automatic translator from other languages based on control graphs, such as Scicos and SyncCharts [61] . Finally, we introduced ``preemption'' in our algorithm model such that it is possible to take into account accurately its cost during off-line scheduling.

We slightly extended our architecture model to take into account program and data memories inside multicomponents. This model is simpler than the hierarchical one described in [25] but is sufficient to be exploited by the code generator in order to minimize the number of buffers by re-using them with coloured graphs techniques.

We extended the architecture model in order to support the specificities of FPGA: internal memories, configuration of computational units, communication unit with other components (cf. SynDEx-IC section).


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