Parallel and distributed simulation from many cores to the public cloud

In these days two main changes are revolutionizing the execution architectures used to run simulations: on the bottom level the processors (CPU) are gaining more and more cores while on the high level we need to cope with virtual resources: "everything as a service" in a Public Cloud infrastructure. Given the magnitude of these changes, what is going to happen to simulation? What are the (many) limits of current approaches, technologies and tools? Is it possible to finally find a solution to some of the many problems of PADS while broadening its scope? In this tutorial we aim to introduce all the basic aspects of these subjects and to discuss the main drawbacks of the current approaches. The main aim of the tutorial is to foster discussion and to increase the knowledge of some now undervalued technologies. The last part of the tutorial will be about our practical experience in the development of the ARTACE simulation middleware and in the proposal of a new paradigm for adaptive distributed simulation (called GAIA) that could be able to tackle with some of the issues described above. The tutorial will conclude with some examples derived from our experience in the performance evaluation of complex systems.