ElasticSimMATE: a Fast and Accurate gem5 Trace-Driven Simulator for Multicore Systems

International audienceMulticore system analysis requires efficient solutions for architectural parameter and scalability exploration. Long simulation time is the main drawback of current simulation approaches. In order to reduce the simulation time while keeping the accuracy levels, trace-driven simulation approaches have been developed. However, existing approaches do not allow multicore exploration or do not capture the behavior of multi-threaded programs. Based on the gem5 simulator, we developed a novel synchronization mechanism for multicore analysis based on the trace collection of synchronization events, instruction and dependencies. It allows efficient architectural parameter and scalability exploration with acceptable simulation speed and accuracy

Method for dynamic power monitoring on FPGAs

International audienceThe ever-increasing integration densities make it possible to configure multi-core systems composed of hundreds of blocks on existing FPGAs that may influence overall consumption differently. Observing total consumption is not sufficient to accurately assess internal circuit activity to be able to deploy effective adaptation strategies. In this case monitoring techniques are required. This paper presents a CAD flow for high-level dynamic power estimation on FPGAs. The method is based on the monitoring of toggling activity for relevant signals by introducing event counters. The appropriate signals are selected using the Greedy Stepwise filter. Our approach is based on a generic method that is able to produce a power model for any block-based circuit. We evaluated our contribution on a SoC RTL model implemented on Spartan3, Virtex5, and Spartan6 FPGAs. A power model and monitors are automatically generated to achieve the best tradeoff between accuracy and overhead

Flexible and Distributed Real-Time Control on a 4G Telecom MPSoC

International audienceApplications like 4G baseband modem require single-chip implementation to meet the integration and power consumption requirements. These applications demand a high computing performance with real-time constraints, low-power consumption and low cost. With the rapid evolution of telecom standards and the increasing demand for multi-standard products, the need for exible baseband solutions is growing. The concept of Multi-Processor System-on-Chip (MPSoC) is well adapted to enable hardware reuse between products and between multiple wireless standards in the same device. Based on the experience of two heterogeneous Software Defined Radio (SDR) telecom chipsets, this paper presents a distributed control architecture for the homoGENEous Processor arraY (GENEPY) platform for 4G applications. This MPSoC platform is built with telecom baseband processors interconnected with a Network-on-Chip. The control is performed by a MIPS processor embedded in each baseband processor. This control processor can locally reconfigure and schedule the applications with real-time telecom constraints

Heterogeneous vs Homogeneous MPSoC Approaches for a Mobile LTE Modem

International audienceApplications like 4G baseband modem require single-chip implementation to meet the integration and power consumption requirements. These applications demand a high computing performance with real-time constraints, low-power consumption and low cost. With the rapid evolution of tele- com standards and the increasing demand for multi-standard products, the need for flexible baseband solutions is growing. The concept of Multi-Processor System-on-Chip (MPSoC) is well adapted to enable hardware reuse between products and between multiple wireless standards in the same device. Heterogeneous architectures are well known solutions but they have limited flexibility. Based on the experience of two heterogeneous Software De- fined Radio (SDR) telecom chipsets, this paper presents the homoGENEous Processor arraY (GENEPY) platform for 4G ap- plications. This platform is built with SMEP units interconnected with a Network-on-Chip. The SMEP, implemented in 65nm low- power CMOS, can perform 3.2 GMAC/s with 77 GBits/s internal bandwidth at 400MHz. Two implementations of homogeneous GENEPY are compared to the heterogeneous MAGALI platform in terms of silicon area, performance and power consumption. Results show that a homogeneous approach can be more efficient and flexible than a heterogeneous approach in the context of 4G Mobile Terminals

A trace-driven approach for fast and accurate simulation of manycore architectures

International audienceThe evolution of manycore sytems, forecasted to feature hundreds of cores by the end of the decade calls for efficient solutions for design space exploration and debugging. Among the relevant existing solutions the well-known gem5 simu-lator provides a rich architecture description framework. However , these features come at the price of prohibitive simulation time that limits the scope of possible explorations to configurations made of tens of cores. To address this limitation, this paper proposes a novel trace-driven simulation approach for efficient exploration of manycore architectures

Hardware Engines for Bus Encryption: a Survey of Existing Techniques

International audienceHardware Engines for Bus Encryption: a Survey of Existing Technique

Normally-Off Computing and Checkpoint/Rollback for Fast, Low-Power, and Reliable Devices

International audienceSince the advent of complementary metal oxide semiconductors (CMOS), the number of transistors per die has continued to increase, reaching today several billion transistors. As a result, it has been possible to design and fabricate smart devices able to run at high speed. However, the power consumption of systems-on-chip has significantly increased due to the high density integration and the high leakage power of current CMOS transistors. As a result, the limits of heat dissipation make further improvement in performance difficult. A high level of autonomy for battery-powered devices is a real challenge. To deal with these issues, spin-transfer-torque magnetic random-access memory (STT-MRAM) technology is seen as a promising solution. In addition to its attractive performance features, STT-MRAM can bring nonvolatility to a system to allow full data retention after a complete shutdown while maintaining a fast wake-up time. Considering two 32-bit embedded processors, this letter shows how STT-MRAM can improve energy efficiency and reliability of future embedded systems thanks to normally-off computing and checkpointing/rollback techniques. A detailed analysis is performed to evaluate the cost related to the backup/recovery of the system. Index Terms—Spintronic memory and logic, embedded processor, spin-transfer-torque, magnetic random-access memory

Exploiting memory allocations in clusterized many-core architectures

Power-efficient architectures have become the most important feature required for future embedded systems. Modern designs, like those released on mobile devices, reveal that clusterization is the way to improve energy efficiency. However, such architectures are still limited by the memory subsystem (i.e., memory latency problems). This work investigates an alternative approach that exploits on-chip data locality to a large extent, through distributed shared memory systems that permit efficient reuse of on-chip mapped data in clusterized many-core architectures. First, this work reviews the current literature on memory allocations and explore the limitations of cluster-based many-core architectures. Then, several memory allocations are introduced and benchmarked scalability, performance and energy-wise, compared to the conventional centralized shared memory solution to reveal which memory allocation is the most appropriate for future mobile architectures. Our results show that distributed shared memory allocations bring performance gains and opportunities to reduce energy consumption