Philipp Gorski

Centralized traffic monitoring for online-resizable clusters in Networks-on-Chip

Runtime-based traffic monitoring is one of the most essential system services for modern many-core platforms. It ensures self-awareness of the current system load and enables other runtime mechanisms, like application mapping and adaptive routing, to optimize workload operations. While Networks-on-Chip introduced a scalable and massively parallel communication infrastructure for the growing number of on-chip resources, scalable traffic monitoring becomes a key concern. A high degree of runtime adaptivity at different system layers comes with the costs that monitored system states need to be available at different locations, scopes and resolutions. Furthermore, many-core systems with hundreds of resources will be less single purpose and run workloads composed of various application domains, traffic and timing characteristics. Thus, the monitoring operations should be adaptive to consider this variability and provide customizable behavior. In the work at hand, a runtime configurable and cluster-based traffic monitoring is proposed. Our experiments show that in maximum 2% hardware overhead per tile in an 8×8 NoC is needed to enable online resizable clustering of up to 64 IP cores, centralized traffic monitoring of all path and link loads inside these clusters at resolutions of 1%, and configurable monitoring timing adjustment in a range of 103 to 105 clock cycles.

Functional enhancements of TMR for power efficient and error resilient ASIC designs

Progressive technology scaling raises the need for efficient VLSI design methods facing the increasing vulnerability to permanent physical defects, while considering power efficiency of resulting circuit implementations at the same time. Triple Modular Redundancy (TMR) represents a common method to encounter reliability problems, but has the drawback of increased area and power consumption. This work introduces a Low Power Redundant (LPR) design solution that targets the power penalty of TMR implementations. This is done by enhanced and new functional runtime capabilities for error detection and operation control. By exploiting the inherent modularity and parallelism of TMR, the LPR solution applies additional control logic to switch dynamically between compare phases (to indicate faults and their locations) and parallel operation (with reduced operation frequency). This allows power optimized circuit operation with full support for the treatment of permanent faults. Simulation results on different ALU implementations show a decrease of power consumption of up to 60 % compared to conventional TMR. Furthermore, different strategies for the switching between operation modes are introduced that enable power efficient system operation in the presence of permanent physical defects. Moreover, significant reliability improvements are also achieved due to the adaptive use of the redundant modules.

Location based wireless sensor services in life science automation

Over the last years Wireless Sensor Networks (WSN) have been becoming increasingly applicable for real world scenarios and now production ready solutions are available. In the same period the upcoming combination of Service-oriented Architectures and Web Service technology demonstrated a way to realize open standardized, flexible, service component based, loosely coupled and interoperable cross domain enterprise software solutions. But those solutions have been too resource-intensive and complex to be applicable for limited devices like wireless sensor nodes or small-sized embedded systems. Thus, more and more research investigations have been launched to bring the aspect of cross domain interoperability to the field of embedded battery powered devices. The proposed laboratory assistance solution in this paper demonstrates the benefits of Web Service enabled WSNs for process monitoring and disaster management by extending an existing system in the Life Science Automation domain. Especially, the capability to provide location based services in industrial automation environment represents a beneficial feature of the presented integration approach and results in high-quality information delivery bundled with specific data about the locational origin of the capturing sensor.

Wireless Sensor Networks in Life Science applications

Over the last years Wireless Sensor Networks (WSN) have been becoming increasingly applicable for real world scenarios and now production ready solutions are available. In the same period the upcoming combination of Service-oriented Architectures and Web Service technology demonstrated a way to realize open standardized, flexible, service component based, loosely coupled and interoperable cross domain Enterprise Software solutions. But those solutions have been too resource-intensive and complex to be applicable for limited devices like wireless sensor nodes or small-sized embedded systems. Thus, more and more research investigations have been launched to bring the aspect of cross domain interoperability to the field of embedded battery powered devices. Now it is time to show the potential of integrating Web Services enabled WSN solutions in Enterprise systems. The proposed laboratory assistance solution in this paper demonstrates the benefits of Web Service enabled WSNs for process monitoring and disaster management by extending an existing system in the Life Science Automation domain.

Selective redundancy to improve reliability and to slow down delay degradation due to gate oxide breakdown

Because of the aggressive scaling into the nanometer regime, degradation due to wearout significantly impairs design parameters. For instance, such wearout is caused by gate oxide breakdown, which decreases the operating lifetime of integrated circuits to an extent that cannot be neglected by circuit designers to date. In this paper, we introduce an approach which applies selective redundancy to different combinational designs in order to improve reliability as regards gate oxide breakdown. Therefore, the most vulnerable transistor stacks of standard cells are doubled based on activity and the propagation delay of the design. Finally, reliability improvements of up to 75% are presented that are gained with Spice simulations. Such improvements come at the price of overhead for area and power consumption as well as delay of at most 14%. However, it is interesting to notice that the initial delay penalty of our enhanced designs finally turn into a timing advantage, as the designs are more and more affected by wearout over time. Hence, this advantage translates into further reliability improvements when clock requirements are also considered. Besides, it needs to be noted that the presented strategies can additionally improve defect yield.

Centralized and Software-Based Run-Time Traffic Management Inside Configurable Regions of Interest in Mesh-Based Networks-on-Chip

This work proposes the introduction of multiple spatially independent network interfaces in order to connect computational resources to mesh-based Networks-on-Chip (NoCs). Furthermore, a flexible system for traffic monitoring is introduced supporting runtime reconfigurability as well as software-based centralized data aggregation and evaluation. These approaches are combined to form a sophisticated framework for runtime traffic management of NoC-based many-core systems exploiting the dual-path options of the underlying network.

Trading Hardware Overhead for Communication Performance in Mesh-Type Topologies

Several alternatives of mesh-type topologies have been published for the use in Networks-on-Chip. Due to their regularity, mesh-type topologies often serve as a foundation to investigate new ideas or to customize the topology to application-specific needs. This paper analyzes existing mesh-type topologies and compares their characteristics in terms of communication and implementation costs. Furthermore, this paper proposes BEAM (Border-Enhanced Mesh) − a mesh-type topology for Networks-on-Chip. BEAM uses concentration while necessitating only low-radix routers. Thereto, additional resources are connected to the outer boundaries of a conventional mesh. As a result, overall bandwidth is traded off against hardware overhead. In conclusion, simulation and synthesis results show that the conventional mesh stands out due to its communication performance, whereas clustered and concentrated topologies offer the least hardware overhead. BEAM ranges in between and is an option to balance hardware costs and communication performance.