Integrated simulation and emulation using adaptive time dilation

Abstract

Simulation and emulation techniques are commonly used to evaluate the performance of complex networked systems. Simulation conveniently predicts the behavior of a complex networked system while usually requiring fewer simplifying model assumptions often necessary for theoretical analysis. In contrast, emulation does not need to re-implement the target real systems, so it may improve on the implementation efficiency of simulation while maintaining much of the realism of testbeds. A hybrid approach in which simulation nodes connect to emulation hosts can be used to combine the advantages of both approaches. In this paper, we propose integrating simulation with emulation using adaptive time dilation to evaluate system performance. If a simulator schedules its events in real time and the simulation time keeps up with the real time, then the hybrid system works very well and meets its deadlines. However, a heavily-loaded simulator can introduce significant simulation delays and thereby create situations where these delays impact the accuracy of the system. Our approach uses time dilation to reduce simulation delays and thus increasing the accuracy of the integrated simulation and emulation system. Our adaptive time dilation dynamically controls the time dilation factor to avoid system overloads for both the simulation and the emulation components and to improve the execution correctness of the hybrid system.

Time managed virtualization for simulating systems of systems

“…Adaptations of existing virtualization tools have been proposed in various forms to address this problem; see [44,47,18,13,23,43,21] for a sampling of these efforts. Virtualization tools simulate the hardware needed to execute software and do so quickly by leveraging real hardware to accelerate the simulation.…”

“…At first glance, it may appear that there is nothing to do. Virtualization technology is readily available, and nearly two decades of research have explored its use within simulations [44,47,18,13,23,43,21]. Moreover, computer system simulators are routinely used by computer architects and embedded software programmers to examine software "as is" in a simulation.…”

Untitled

“…Finally, related work concerns embedding emulators in virtual time (Zheng et al 2012b;Grau et al 2008;Gupta et al 2011;Erazo et al 2009;Weingärtner et al 2011;Lee et al 2014;). SVEET (Erazo et al 2009) and DieCast (Gupta et al 2011) both make modifications to the Xen hypervisor in order to give each VM a notion of virtual time.…”

Conjoining Emulation and Network Simulators on Linux Multiprocessors

“…Bringing virtual time to a computer system is not a new idea, as many recent papers have explored this concept [27,12,13,11,24,18]. SVEET!…”