Electronic System Level (ESL)

Extreme Edge AI: Execution of Machine Learning Workloads on MCUs / IoT Nodes

A new research direction of our group is to investigate how to run Artificial Neural Network(ANN)  workloads for deep learning edge application such as Keyword recognition efficiently on Low-power IoT devices at the extreme edge. These devices are usually highly resource constrained, e.g. based on Micro-Controller Units (MCUs), which only have very limited memory and computing resources.

Current research directions
  • Distributed Inference: Here we investigate methods to partition Neural Networks such that they can be executed in a distributed fashion on a network of IoT nodes.
  • Offline Execution-Planning and code generation: Here we investigate methods to generate, e.g., from TensorFlow Lite, and optimize the embedded software offline to minimize memory and performance overheads for inference on extreme edge devices.
Selected Publications on TinyML

Saman Payvar, Mir Khan, Rafael Stahl, Daniel Mueller-Gritschneder, Jani Boutellier
Neural Network-based Vehicle Image Classification for IoT Devices
In: International Workshop on Signal Processing Systems (SiPS)
October 2019

Rafael Stahl, Zhuoran Zhao, Daniel Mueller-Gritschneder, Andreas Gerstlauer, Ulf Schlichtmann
Fully Distributed Deep Learning Inference on Resource-Constrained Edge Devices
In: International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS)
July 2019

Runtime Verification

Traditional verification methods such as testing and model checking do not scale with the complexity of today’s embedded systems. This problem is addressed by runtime verification which verifies the execution behavior of a system against a set of runtime requirements. In this process, the system of interest is instrumented to extract events of the system. This trace of events is then analyzed by a runtime monitor, which infers a positive verdict while the trace fulfills all runtime requirements and a negative verdict once a requirement is violated. Application areas for RV are testing and debugging before deployment, and fault recovery, reliability and safety after deployment.

Current Research Directions
  • Hardware-based Monitoring Approaches: We investigate scalable monitoring architectures in HW for tile-based systems.
  • Emulation of ASIC Sensors for FPGA Prototypes: We emulate ASIC power, temperature and aging sensors, which enable the prototyping of system managers on FPGAs.
Selected Publications on Runtime Verification

Marcel Mettler, Daniel Mueller-Gritschneder, Ulf Schlichtmann
Runtime Monitoring of Inter- and Intra-Thread Requirements on Embedded MPSoCs
2020 33rd International Conference on VLSI Design and 2020 19th International Conference on Embedded Systems (VLSID)
January 2020

Alexandra Listl, Daniel Mueller-Gritschneder, Fabian Kluge, Ulf Schlichtmann
Emulation of an ASIC Power, Temperature and Aging Monitor System for FPGA Prototyping
In: IEEE International On-Line Testing Symposium (IOLTS)
July 2018

Virtual Prototypes for Embedded SW Development and Safety Evaluation

The ever increasing integration scale and architecture complexity of embedded systems and SoCs challenge today's simulation and verification methods. This lead to the shift towards Virtual Prototypes and Platforms (VPs). VPs are abstract computer models of the system, embedded electronics and its environment used for Electronic System Level Design (ESL).
In the context of our work VPs are detailed enough to emulate the embedded target software. They can work as platforms for architecture exploration, early software development and system-level verification.

VPs ascend to higher abstraction level than the conventional Register Transfer Level (RTL) for higher simulation performance. Transaction Level Modeling (TLM) using SystemC is a very, if not the most, widely adopted methodology for this purpose. In TLM, communication between modules is abstracted as transaction. Transactions are evoked by (non-clocked) events and realized by function calls.

Current research directions
  • Test-driven development using virtual prototypes: We investigate how virtual prototypes can be leveraged for test-driven development of hardware-near software/firmware.
  • Extendable Dynamic Binary Translation: We developed the Extendable Translating Instruction Set Simulator (ETISS). It is based on Dynamic Binary Translation (DBT) using C-Language as Intermediate Format. ETISS introduced a Plugin-mechanisms that allows to quickly insert new functionality (timing, power profiling, tracing) without need to hack the simulation loop. ETISS is an open source project.
  • Automatic Generation of Firmware Safety Mechanisms: In this projet we target to generate automatic software safety mechanisms for firmware codes.
Past projects
  • Early Functional Safety Evaluation by VP-level Error Injection: In safety-critical applications such as human-robot interaction or assisted and autonomous driving, the system must preserve a safe state even in the presence of HW faults. HW faults in the embedded electronics may be caused by particle strikes onto the integrated curcuits (ICs) due to radiation, IC aging or supply voltage drops. In order to develop future complex systems for safety critical applications, we investigate methods for early evaluation of the safety concepts. We use VPs and VP-level fault injection with focus on CPUs and Firmware safety mechanisms.
  • Host-compiled Simulation: For TLM simulation of SoCs, the emulation of the target SW code can quickly become the performance bottleneck. TUM EDA researches CPU models that can simulate target code siginficantly faster than conventional CPU models. For this we investigate so called host-compiled SW simulation, which compiles the SW directly for the simulation host. Here we developed an annotation tool to recover the timing information of the target SW for ultra-fast but timing-accurate simulation.
Selected Publications on Virtual Prototyping

Daniel Mueller-Gritschneder, Uzair Sharif, Ulf Schlichtmann
Performance and Accuracy in Soft-Error Resilience Evaluation using the Multi-Level Processor Simulator ETISS-ML
In: IEEE/ACM International Conference on Computer-Aided Design (ICCAD)
November 2018
(Invited Paper)

Petra R. Maier, Veit B. Kleeberger, Daniel Mueller-Gritschneder, Ulf Schlichtmann
Fault Injection for Test-Driven Development of Robust SoC Firmware (PDF)
ACM Transactions on Embedded Computing Systems (TECS) 17
November 2017

Daniel Mueller-Gritschneder, Martin Dittrich, Marc Greim, Keerthikumara Devarajegowda, Wolfgang Ecker, Ulf Schlichtmann
The Extendable Translating Instruction Set Simulator (ETISS) interlinked with an MDA Framework for fast RISC Prototyping
In: IEEE International Symposium on Rapid System Prototyping (RSP)
October 2017

Design Space Exploration of Application-specific Networks-on-Chip (NoCs)

Rising complexity of modern SoCs leads to increasing communication between the cores. Networks-on-chip (NoCs) have been proposed as new communication architecture because they are expected to scale better with the increasing communication demands.

If the application is known at design time, custom SoC chips also require a custom appplication-specific NoC structure. In this project,  Design Space Exploration (DSE) methods are investigated that find NoC stuctures, which feature an optimal compromise between area, power and latencies.

Research directions

Applying Machine Learning for Design Space Exploration: In this project we are using methods from the field of machine learning such as graph grammars, Monte Carlo Tree Search and Deep Learning techniques to efficiently explore the design space of application-specific NoCs.

Selected Publications on Application-specific NoC Synthesis

Yong Hu, Daniel Mueller-Gritschneder, Ulf Schlichtmann
Wavefront-MCTS: Multi-objective Design Space Exploration of NoC Architectures based on Monte Carlo Tree Search
In: IEEE/ACM International Conference on Computer-Aided Design (ICCAD)
November 2018

Yong Hu, Daniel Mueller-Gritschneder, Sepulveda, M.J., Gogniat, G., Ulf Schlichtmann
Automatic ILP-based Firewall Insertion for Secure Application-Specific Networks-on-Chip
In: Interconnection Network Architectures: On-Chip, Multi-Chip (INA-OCMC), 2015 Ninth International Workshop on
January 2015

Vladimir Todorov, Daniel Mueller-Gritschneder, Helmut Reinig, Ulf Schlichtmann
Deterministic Synthesis of Hybrid Application-Specific Network-on-Chip Topologies
Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on 33(10), 1503-1516
October 2014

Vladimir Todorov, Daniel Mueller-Gritschneder, Helmut Reinig, Ulf Schlichtmann
A Spectral Clustering Approach to Application-Specific Network-on-Chip Synthesis
In: Design, Automation and Test in Europe (DATE)
March 2013