Thomas Wild

Thomas Wild

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Thomas Wild

Chair of Integrated Systems, Technical University of Munich, Munich, Germany

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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21 September 2005 in Design Automation for Embedded Systems
Verified
Journal Article
Open access
PDF file
TWThomas Wild
Thomas Wild
AHAndreas Herkersdorf
Andreas Herkersdorf
GLGyoo-Yeong Lee
Gyoo-Yeong Lee
The design of today’s System-on-Chip (SoC) architectures faces many challenges in respect to the involved complexity and heterogeneity. An early and systematic exploration of alternatives is mandatory to find a solution that meets all design requirements. Therefore, the experience of system architects has to be supplemented with efficient performance evaluation methods and tools that help in the broad exploration of the solution space. This article describes TAPES (Trace-based Architecture Performance Evaluation with SystemC), an approach that supports system designers in the performance evaluation of SoC architectures. The concept captures the functionality of the architecture in the form of traces for each resource. The trace primitives making up a trace are translated at simulation run-time into transactions and superposed on the system architecture. The method uses SystemC as modeling language, requires low modeling effort and yet provides accurate results within reasonable turnaround times. A concluding application example for the exploration of a network processor architecture demonstrates the effectiveness of the TAPES approach.

1 September 2018 in Proceedings of the IEEE
Verified
Journal Article
Open access
MMMischa Mostl
Mischa Mostl
JSJohannes Schlatow
Johannes Schlatow
RERolf Ernst
Rolf Ernst
NDNikil Dutt
Nikil Dutt
ANAhmed Nassar
Ahmed Nassar
AHAndreas Herkersdorf
Andreas Herkersdorf
Future cyber-physical systems will host a large number of coexisting distributed applications on hardware platforms with thousands to millions of networked components communicating over open networks. These applications and networks are subject to continuous change. The current separation of design process and operation in the field will be superseded by a life-long design process of adaptation, infield integration, and update. Continuous change and evolution, application interference, environment dynamics and uncertainty lead to complex effects which must be controlled to serve a growing set of platform and application needs. Self-adaptation based on self-awareness and self-configuration has been proposed as a basis for such a continuous in-field process. Research is needed to develop automated in-field design methods and tools with the required safety, availability, and security guarantees. The paper shows two complementary use cases of self-awareness in architectures, methods, and tools for cyber-physical systems. The first use case focuses on safety and availability guarantees in self-aware vehicle platforms. It combines contracting mechanisms, tool based self-analysis and self-configuration. A software architecture and a runtime environment executing these tools and mechanisms autonomously are presented including aspects of self-protection against failures and security threats. The second use case addresses variability and long term evolution in networked MPSoC integrating hardware and software mechanisms of surveillance, monitoring, and continuous adaptation. The approach resembles the logistics and operation principles of manufacturing plants which gave rise to the metaphoric term of an Information Processing Factory that relies on incremental changes and feedback control. Both use cases are investigated by larger research groups. Despite their different approaches, both use cases face similar design and design automation challenges which will be summarized in the end. We will argue that seemingly unrelated research challenges, such as in machine learning and security, could also profit from the methods and superior modeling capabilities of self-aware systems.

1 November 2020 in IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Verified
Journal Article
Closed access
MSMark Sagi
Mark Sagi
NDNguyen Anh Vu Doan
Nguyen Anh Vu Doan
MRMartin Rapp
Martin Rapp
TWThomas Wild
Thomas Wild
JHJorg Henkel
Jorg Henkel
AHAndreas Herkersdorf
Andreas Herkersdorf

1 August 2018
Verified
Conference Paper
Closed access
AOAndreas Oeldemann
Andreas Oeldemann
TWThomas Wild
Thomas Wild
AHAndreas Herkersdorf
Andreas Herkersdorf
We present FlueNT10G, an open-source FPGA-based network tester for precise replay of network traces, as well as for accurate packet capture and round-trip latency measurements. FlueNT10G streams replay and capture data between the host system and the FPGA board during active tests. It enables continuous measurements without being constrained by the memory capacity of the FPGA board. FlueNT10G is able to concurrently replay and capture traffic on three 10 Gbit/s network interfaces for all packet sizes. When operated exclusively in replay or capture mode, throughput increases to 4x 10 Gbit/s. Our design yields a temporal resolution of 6.4 ns for precise traffic pattern generation, as well as for accurate arrival timestamping and latency measurements. On the software-side, FlueNT10G is complemented by an API enabling the programmable execution of reproducible network measurements. Targeting the automated performance evaluation of different virtualized network function configurations, the API further integrates access to a bidirectional side-band channel for device-under-test reconfiguration and status feedback. FlueNT10G has been implemented on the NetFPGA-SUME platform (Xilinx Virtex-7 XC7VX690T) with an FPGA resource utilization of no more than 25%, which leaves sufficient capacity available for future design extensions.

29 March 2022 in International Journal of Parallel Programming
Verified
Journal Article
Open access
PDF file
MSMark Sagi
Mark Sagi
NDNguyen Anh Vu Doan
Nguyen Anh Vu Doan
NFNael Fasfous
Nael Fasfous
TWThomas Wild
Thomas Wild
AHAndreas Herkersdorf
Andreas Herkersdorf
To minimize power consumption while maximizing performance, today’s multicore processors rely on fine-grained run-time dynamic power information—both in the time domain, e.g. $$\mu $$ μ s to ms, and space domain, e.g. core-level. The state-of-the-art for deriving such power information is mainly based on predetermined power models which use linear modeling techniques to determine the core-performance/core-power relationship. However, with multicore processors becoming ever more complex, linear modeling techniques cannot capture all possible core-performance related power states anymore. Although artificial neural networks (ANN) have been proposed for coarse-grained power modeling of servers with time resolutions in the range of seconds, few works have yet investigated fine-grained ANN-based power modeling. In this paper, we explore feed-forward neural networks (FFNNs) for core-level power modeling with estimation rates in the range of 10 kHz. To achieve a high estimation accuracy while minimizing run-time overhead, we propose a multi-objective-optimization of the neural architecture using NSGA-II with the FFNNs being trained on performance counter and power data from a complex-out-of-order processor architecture. We show that relative power estimation error for the highest accuracy FFNN decreases on average by 7.5% compared to a state-of-the-art linear power modeling approach and decreases by 5.5% compared to a multivariate polynomial regression model. For the FFNNs optimized for both accuracy and overhead, the average error decreases between 4.1% and 6.7% compared to linear modeling while offering significantly lower overhead compared to the highest accuracy FFNN. Furthermore, we propose a micro-controller-based and an accelerator-based implementation for run-time inference of the power modeling FFNN and show that the area overhead is negligible.

19 September 2008 in IEEE Transactions on Very Large Scale Integration (VLSI) Systems
Verified
Journal Article
Closed access
RORainer Ohlendorf
Rainer Ohlendorf
MMMichael Meitinger
Michael Meitinger
TWThomas Wild
Thomas Wild
AHAndreas Herkersdorf
Andreas Herkersdorf
Multi-field packet classification problems discussed in the literature are typically constrained to the Internet five-tuple and primarily address the problem of network quality-of-service (QoS) support and access control. In this paper, we present a solution for a classification problem that is used for optimized packet assignment to different data paths within a network processor system-on-chip (SoC). In contrast to the five-tuple-based rules discussed in the prior art, our problem has rules that consider a larger set of fields from the packet header. However, for each individual rule a different sub-set of fields is relevant and the number of rules is smaller. Based on a specification of the usage case for our classifier we derive heterogeneous decision graph algorithm (HDGA), a heuristic approach to construct a decision tree classifier that integrates external lookup results for certain types of rules. We evaluate various parameters for optimizing the proposed decision tree and present simulation results to show the scalability of HDGA for typical problem sizes. This paper is concluded with the results of an implementation on our field-programmable gate-array (FPGA)-based prototyping platform.