ESP is an open-source research platform for heterogeneous SoC design. The platform combines a modular tile-based architecture with a variety of application-oriented flows for the design and optimization of accelerators. The ESP architecture is highly scalable and strikes a balance between regularity and specialization. The companion methodology raises the level of abstraction to system-level design and enables an automated flow from software and hardware development to full-system prototyping on FPGA. For application developers, ESP offers domain-specific automated solutions to synthesize new accelerators for their software and to map complex workloads onto the SoC architecture. For hardware engineers, ESP offers automated solutions to integrate their accelerator designs into the complete SoC. Conceived as a heterogeneous integration platform and tested through years of teaching at Columbia University, ESP supports the open-source hardware community by providing a flexible platform for agile SoC development.

From a single SoC to a network of embedded devices communicating with a backend cloud-computing server, emerging classes of embedded systems feature an increasing number of heterogeneous components that operate concurrently in a distributed environment. As the scale and complexity of these systems continues to grow, there is a critical need for scalable and efficient simulators. We propose a networked virtual platform as a scalable environment for modeling and simulation. The goal is to support the development and optimization of embedded computing applications by handling heterogeneity at the chip, node, and network level. To illustrate the properties of our approach, we present two very different case studies: the design of an Open MPI scheduler for a heterogeneous distributed embedded system and the development of an application for crowd estimation through the analysis of pictures uploaded from mobile phones.

Virtual channels (VC) and multiple physical (MP) networks are two alternative methods to provide better performance, support quality-of-service, and avoid protocol deadlocks in packet-switched network-on-chip design. Since contention can be dynamically resolved, VCs give lower zero-load packet latency than MPs; however, MPs can be built with simpler routers and narrower channels, which improves the target clock frequency, power dissipation, and area occupation. In this paper, we present a comprehensive comparative analysis of these two design approaches, including an analytical model, synthesis-based designs with both FPGAs and standard-cell libraries, and system-level simulations. The result of our analysis shows that one solution does not outperform the other in all the tested scenarios. Instead, each approach has its own specific strengths and weaknesses. Hence, we identify the scenarios where each method is best suited to achieve high performance, very low power dissipation, and increased design flexibility.

The growing complexity of System-on-Chip (SoC) design calls for an increased usage of transaction-level modeling (TLM), high-level synthesis tools, and reuse of pre-designed components. In the framework of a compositional methodology for efficient SoC design exploration we present three main contributions: a concise library format for characterization and reuse of components specified in high-level languages like SystemC; an algorithm to prune alternative implementations of a component given the context of a specific SoC design; and an algorithm that explores compositionally the design space of the SoC and produces a detailed plan to run high-level synthesis on its components for the final implementation. The two algorithms are computationally efficient and enable an effective parallelization of the synthesis runs. Through a case study, we show how our methodology returns the essential properties of the design space at the system level by combining the information from the library of components and by identifying automatically those having the most critical impact on the overall design.

Technology scaling allows the integration of billions of transistors on the same die but CAD tools struggle in keeping up with the increasing design complexity. Design productivity for multi-core SoCs increasingly depends on creating and maintaining reusable components and hierarchically combining them to form larger composite cores. Characterizing such composite cores with respect to their power/performance tradeoffs is critical for design reuse across various products and relies heavily on synthesis tools. We present CAPS, an online adaptive algorithm that efficiently explores the design space of any given core and returns an accurate characterization of its implementation tradeoffs in terms of an approximate Pareto set. It does so by supervising the order of the time-consuming logic-synthesis runs on the core's components. Our algorithm can provably achieve the desired precision on the approximation in the shortest possible time, without having any a-priori information on any component. We also show that, in practice, CAPS works even better than what is guaranteed by the theory.

Packet-switched networks-on-chip (NoC) have been proposed as an efficient communication infrastructure for multi-core architectures. Adding virtual channels to a NoC helps to avoid deadlock and optimize the bandwidth of the physical channels in exchange for a more complex design of the routers. Another, possibly alternative, approach is to build multiple parallel physical networks (multiplanes) with smaller channels and simpler router organizations. We present a comparative analysis of these two approaches based on analytical models and on a comprehensive set of experimental results including both synthesized hardware implementations and system-level simulations.

As the number of processing cores that are integrated into a chip multiprocessors (CMP) continues to grow, the network-on-chip paradigm has emerged as a promising solution to address the problem of providing a robust interconnect network among them. In future high-performance CMPs, however, the high bandwidth requirements for both intra-chip and off-chip communication are severely challenging the electronic communications infrastructure to meet these demands without consuming a large fraction of the overall on-chip power-dissipation budget. The introduction of photonic technology for on-chip communication holds the promise of delivering scalable bandwidth-per-watt performance that cannot be achieved using only electronic communication. After reviewing the key recent technologies advances that are making possible the integration of photonic devices with CMOS processes, we describe a hybrid micro-architecture for NoCs that combines a broadband photonic circuit-switched network with an electronic packet-switched control network and we discuss the pros and cons of using two different network topologies to implement it.

VoIP has widely been addressed as the technology that will change the Telecommunication model opening the path for convergence. Still today this revolution is far from being complete, since the majority of telephone calls are originated by circuit-oriented networks. In this paper for the first time to the best of our knowledge, we present a large dataset of measurements collected from the FastWeb backbone, which is one of the first worldwide Telecom operator to offer VoIP and high-speed data access to the end-user. Traffic characterization will focus on several layers, focusing on both end-user and ISP perspective. In particular, we highlight that, among loss, delay and jitter, only the first index may affect the VoIP call quality. Results show that the technology is mature to make the final step, allowing the integration of data and real-time services over the Internet.