938 research outputs found
Efficient Neural Network Implementations on Parallel Embedded Platforms Applied to Real-Time Torque-Vectoring Optimization Using Predictions for Multi-Motor Electric Vehicles
The combination of machine learning and heterogeneous embedded platforms enables new potential for developing sophisticated control concepts which are applicable to the field of vehicle dynamics and ADAS. This interdisciplinary work provides enabler solutions -ultimately implementing fast predictions using neural networks (NNs) on field programmable gate arrays (FPGAs) and graphical processing units (GPUs)- while applying them to a challenging application: Torque Vectoring on a multi-electric-motor vehicle for enhanced vehicle dynamics. The foundation motivating this work is provided by discussing multiple domains of the technological context as well as the constraints related to the automotive field, which contrast with the attractiveness of exploiting the capabilities of new embedded platforms to apply advanced control algorithms for complex control problems. In this particular case we target enhanced vehicle dynamics on a multi-motor electric vehicle benefiting from the greater degrees of freedom and controllability offered by such powertrains. Considering the constraints of the application and the implications of the selected multivariable optimization challenge, we propose a NN to provide batch predictions for real-time optimization. This leads to the major contribution of this work: efficient NN implementations on two intrinsically parallel embedded platforms, a GPU and a FPGA, following an analysis of theoretical and practical implications of their different operating paradigms, in order to efficiently harness their computing potential while gaining insight into their peculiarities. The achieved results exceed the expectations and additionally provide a representative illustration of the strengths and weaknesses of each kind of platform. Consequently, having shown the applicability of the proposed solutions, this work contributes valuable enablers also for further developments following similar fundamental principles.Some of the results presented in this work are related to activities within the 3Ccar project, which has
received funding from ECSEL Joint Undertaking under grant agreement No. 662192. This Joint Undertaking
received support from the European Union’s Horizon 2020 research and innovation programme and Germany,
Austria, Czech Republic, Romania, Belgium, United Kingdom, France, Netherlands, Latvia, Finland, Spain, Italy,
Lithuania. This work was also partly supported by the project ENABLES3, which received funding from ECSEL
Joint Undertaking under grant agreement No. 692455-2
Efficiency analysis methodology of FPGAs based on lost frequencies, area and cycles
We propose a methodology to study and to quantify efficiency and the impact of overheads on runtime performance. Most work on High-Performance Computing (HPC) for FPGAs only studies runtime performance or cost, while we are interested in how far we are from peak performance and, more importantly, why. The efficiency of runtime performance is defined with respect to the ideal computational runtime in absence of inefficiencies. The analysis of the difference between actual and ideal runtime reveals the overheads and bottlenecks. A formal approach is proposed to decompose the efficiency into three components: frequency, area and cycles. After quantification of the efficiencies, a detailed analysis has to reveal the reasons for the lost frequencies, lost area and lost cycles. We propose a taxonomy of possible causes and practical methods to identify and quantify the overheads. The proposed methodology is applied on a number of use cases to illustrate the methodology. We show the interaction between the three components of efficiency and show how bottlenecks are revealed
Pixie: A heterogeneous Virtual Coarse-Grained Reconfigurable Array for high performance image processing applications
Coarse-Grained Reconfigurable Arrays (CGRAs) enable ease of programmability
and result in low development costs. They enable the ease of use specifically
in reconfigurable computing applications. The smaller cost of compilation and
reduced reconfiguration overhead enables them to become attractive platforms
for accelerating high-performance computing applications such as image
processing. The CGRAs are ASICs and therefore, expensive to produce. However,
Field Programmable Gate Arrays (FPGAs) are relatively cheaper for low volume
products but they are not so easily programmable. We combine best of both
worlds by implementing a Virtual Coarse-Grained Reconfigurable Array (VCGRA) on
FPGA. VCGRAs are a trade off between FPGA with large routing overheads and
ASICs. In this perspective we present a novel heterogeneous Virtual
Coarse-Grained Reconfigurable Array (VCGRA) called "Pixie" which is suitable
for implementing high performance image processing applications. The proposed
VCGRA contains generic processing elements and virtual channels that are
described using the Hardware Description Language VHDL. Both elements have been
optimized by using the parameterized configuration tool flow and result in a
resource reduction of 24% for each processing elements and 82% for each virtual
channels respectively.Comment: Presented at 3rd International Workshop on Overlay Architectures for
FPGAs (OLAF 2017) arXiv:1704.0880
P4-compatible High-level Synthesis of Low Latency 100 Gb/s Streaming Packet Parsers in FPGAs
Packet parsing is a key step in SDN-aware devices. Packet parsers in SDN
networks need to be both reconfigurable and fast, to support the evolving
network protocols and the increasing multi-gigabit data rates. The combination
of packet processing languages with FPGAs seems to be the perfect match for
these requirements. In this work, we develop an open-source FPGA-based
configurable architecture for arbitrary packet parsing to be used in SDN
networks. We generate low latency and high-speed streaming packet parsers
directly from a packet processing program. Our architecture is pipelined and
entirely modeled using templated C++ classes. The pipeline layout is derived
from a parser graph that corresponds a P4 code after a series of graph
transformation rounds. The RTL code is generated from the C++ description using
Xilinx Vivado HLS and synthesized with Xilinx Vivado. Our architecture achieves
100 Gb/s data rate in a Xilinx Virtex-7 FPGA while reducing the latency by 45%
and the LUT usage by 40% compared to the state-of-the-art.Comment: Accepted for publication at the 26th ACM/SIGDA International
Symposium on Field-Programmable Gate Arrays February 25 - 27, 2018 Monterey
Marriott Hotel, Monterey, California, 7 pages, 7 figures, 1 tabl
Optimizing Scrubbing by Netlist Analysis for FPGA Configuration Bit Classification and Floorplanning
Existing scrubbing techniques for SEU mitigation on FPGAs do not guarantee an
error-free operation after SEU recovering if the affected configuration bits do
belong to feedback loops of the implemented circuits. In this paper, we a)
provide a netlist-based circuit analysis technique to distinguish so-called
critical configuration bits from essential bits in order to identify
configuration bits which will need also state-restoring actions after a
recovered SEU and which not. Furthermore, b) an alternative classification
approach using fault injection is developed in order to compare both
classification techniques. Moreover, c) we will propose a floorplanning
approach for reducing the effective number of scrubbed frames and d),
experimental results will give evidence that our optimization methodology not
only allows to detect errors earlier but also to minimize the
Mean-Time-To-Repair (MTTR) of a circuit considerably. In particular, we show
that by using our approach, the MTTR for datapath-intensive circuits can be
reduced by up to 48.5% in comparison to standard approaches
AutoAccel: Automated Accelerator Generation and Optimization with Composable, Parallel and Pipeline Architecture
CPU-FPGA heterogeneous architectures are attracting ever-increasing attention
in an attempt to advance computational capabilities and energy efficiency in
today's datacenters. These architectures provide programmers with the ability
to reprogram the FPGAs for flexible acceleration of many workloads.
Nonetheless, this advantage is often overshadowed by the poor programmability
of FPGAs whose programming is conventionally a RTL design practice. Although
recent advances in high-level synthesis (HLS) significantly improve the FPGA
programmability, it still leaves programmers facing the challenge of
identifying the optimal design configuration in a tremendous design space.
This paper aims to address this challenge and pave the path from software
programs towards high-quality FPGA accelerators. Specifically, we first propose
the composable, parallel and pipeline (CPP) microarchitecture as a template of
accelerator designs. Such a well-defined template is able to support efficient
accelerator designs for a broad class of computation kernels, and more
importantly, drastically reduce the design space. Also, we introduce an
analytical model to capture the performance and resource trade-offs among
different design configurations of the CPP microarchitecture, which lays the
foundation for fast design space exploration. On top of the CPP
microarchitecture and its analytical model, we develop the AutoAccel framework
to make the entire accelerator generation automated. AutoAccel accepts a
software program as an input and performs a series of code transformations
based on the result of the analytical-model-based design space exploration to
construct the desired CPP microarchitecture. Our experiments show that the
AutoAccel-generated accelerators outperform their corresponding software
implementations by an average of 72x for a broad class of computation kernels
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Memory-Based High-Level Synthesis Optimizations Security Exploration on the Power Side-Channel
High-level synthesis (HLS) allows hardware designers to think algorithmically and not worry about low-level, cycle-by-cycle details. This provides the ability to quickly explore the architectural design space and tradeoffs between resource utilization and performance. Unfortunately, security evaluation is not a standard part of the HLS design flow. In this article, we aim to understand the effects of memory-based HLS optimizations on power side-channel leakage. We use Xilinx Vivado HLS to develop different cryptographic cores, implement them on a Spartan-6 FPGA, and collect power traces. We evaluate the designs with respect to resource utilization, performance, and information leakage through power consumption. We have two important observations and contributions. First, the choice of resource optimization directive results in different levels of side-channel vulnerabilities. Second, the partitioning optimization directive can greatly compromise the hardware cryptographic system through power side-channel leakage due to the deployment of memory control logic. We describe an evaluation procedure for power side-channel leakage and use it to make best-effort recommendations about how to design more secure architectures in the cryptographic domain
Optimized Architectural Synthesis of Fixed-Point Datapaths
In this paper we address the time-constrained architectural synthesis of fixed-point DSP algorithms using FPGA devices. Optimized fixed-point implementations are obtained by means of considering: (i) a multiple wordlength approach; (ii) a complete datapath formed of wordlength-wise resources (i.e. functional units, multiplexers and registers); and, (iii) a novel resource usage metric that enables the wise distribution of logic fabric and embedded DSP resources. The paper shows: (i) the benefits of applying a multiple wordlength approach to the implementation of fixedpoint datapaths; and (ii) the benefits of a wise use of embedded FPGA resources. The proposed metric enables area improvements up to 54% and the use of a complete fixed-point datapath leads to improvements up to 35%
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