Multilevel simulation-based co-design of next generation HPC microprocessors

This paper demonstrates the combined use of three simulation tools in support of a co-design methodology for an HPC-focused System-on-a-Chip (SoC) design. The simulation tools make different trade-offs between simulation speed, accuracy and model abstraction level, and are shown to be complementary. We apply the MUSA trace-based simulator for the initial sizing of vector register length, system-level cache (SLC) size and memory bandwidth. It has proven to be very efficient at pruning the design space, as its models enable sufficient accuracy without having to resort to highly detailed simulations. Then we apply gem5, a cycle-accurate micro-architecture simulator, for a more refined analysis of the performance potential of our reference SoC architecture, with models able to capture detailed hardware behavior at the cost of simulation speed. Furthermore, we study the network-on-chip (NoC) topology and IP placements using both gem5 for representative small- to medium-scale configurations and SESAM/VPSim, a transaction-level emulator for larger scale systems with good simulation speed and sufficient architectural details. Overall, we consider several system design concerns, such as processor subsystem sizing and NoC settings. We apply the selected simulation tools, focusing on different levels of abstraction, to study several configurations with various design concerns and evaluate them to guide architectural design and optimization decisions. Performance analysis is carried out with a number of representative benchmarks. The obtained numerical results provide guidance and hints to designers regarding SIMD instruction width, SLC sizing, memory bandwidth as well as the best placement of memory controllers and NoC form factor. Thus, we provide critical insights for efficient design of future HPC microprocessors.This work has been performed in the context of the European Processor Initiative (EPI) project, which has received funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement № 826647. A special thanks to Amir Charif and Arief Wicaksana for their invaluable contributions to the SESAM/VPSim tool in the initial phases of the EPI project.Peer ReviewedPostprint (author's final draft

Co-simulation of a Model Predictive Control System for Automotive Application

International audienceDesigning a Model Predictive Control system requires an accurate analysis of the interplay among three main components: the plant, the control algorithm, and the processor where the algorithm is executed. A main objective of this analysis is determining if the controller running on the chosen hardware meets the time requirements and response time of the plant. The constraints, in turn, should be met with a satisfactory tradeoff between algorithm complexity and processor performance. To carry out these analyses for an autonomous vehicle control, this paper proposes to leverage parallel co-simulation between the plant, the model predictive controller and the processor

Multilevel simulation-based co-design of next generation HPC microprocessors

International audienceThis paper demonstrates the combined use of three simulation tools in support of a co-design methodology for an HPC-focused System-on-a-Chip (SoC) design. The simulation tools make different trade-offs between simulation speed, accuracy and model abstraction level, and are shown to be complementary. We apply the MUSA trace-based simulator for the initial sizing of vector register length, system-level cache (SLC) size and memory bandwidth. It has proven to be very efficient at pruning the design space, as its models enable sufficient accuracy without having to resort to highly detailed simulations. Then we apply gem5, a cycle-accurate micro-architecture simulator, for a more refined analysis of the performance potential of our reference SoC architecture, with models able to capture detailed hardware behavior at the cost of simulation speed. Furthermore, we study the network-on-chip (NoC) topology and IP placements using both gem5 for representative small- to medium-scale configurations and SESAM/VPSim, a transaction-level emulator for larger scale systems with good simulation speed and sufficient architectural details.Overall, we consider several system design concerns, such as processor subsystem sizing and NoC settings. We apply the selected simulation tools, focusing on different levels of abstraction, to study several configurations with various design concerns and evaluate them to guide architectural design and optimization decisions. Performance analysis is carried out with a number of representative benchmarks. The obtained numerical results provide guidance and hints to designers regarding SIMD instruction width, SLC sizing, memory bandwidth as well as the best placement of memory controllers and NoC form factor. Thus, we provide critical insights for efficient design of future HPC microprocessors

Multilevel simulation-based co-design of next generation HPC microprocessors

This paper demonstrates the combined use of three simulation tools in support of a co-design methodology for an HPC-focused System-on-a-Chip (SoC) design. The simulation tools make different trade-offs between simulation speed, accuracy and model abstraction level, and are shown to be complementary. We apply the MUSA trace-based simulator for the initial sizing of vector register length, system-level cache (SLC) size and memory bandwidth. It has proven to be very efficient at pruning the design space, as its models enable sufficient accuracy without having to resort to highly detailed simulations. Then we apply gem5, a cycle-accurate micro-architecture simulator, for a more refined analysis of the performance potential of our reference SoC architecture, with models able to capture detailed hardware behavior at the cost of simulation speed. Furthermore, we study the network-on-chip (NoC) topology and IP placements using both gem5 for representative small- to medium-scale configurations and SESAM/VPSim, a transaction-level emulator for larger scale systems with good simulation speed and sufficient architectural details. Overall, we consider several system design concerns, such as processor subsystem sizing and NoC settings.We apply the selected simulation tools, focusing on different levels of abstraction, to study several configurations with various design concerns and evaluate them to guide architectural design and optimization decisions. Performance analysis is carried out with a number of representative benchmarks. The obtained numerical results provide guidance and hints to designers regarding SIMD instruction width, SLC sizing, memory bandwidth as well as the best placement of memory controllers and NoC form factor.Thus, we provide critical insights for efficient design of future HPC microprocessors