TY - GEN A1 - Prescher, Thomas A1 - Rotta, Randolf A1 - Nolte, Jörg T1 - Flexible Sharing and Replication Mechanisms for Hybrid Memory Architectures T2 - Proceedings of the 4th Many-Core Applications Research Community (MARC) Symposium Y1 - 2011 SN - 978-3-86956-169-1 SP - 67 EP - 72 PB - Univ.-Verl. CY - Potsdam ER - TY - GEN A1 - Rotta, Randolf T1 - On Efficient Message Passing on the Intel SCC T2 - Proceedings, 3rd Many-core Applications Research Community (MARC) Symposium Y1 - 2011 SN - 978-3-86644-717-2 SP - 53 EP - 58 PB - KIT Scientific Publishing CY - Karlsruhe ER - TY - GEN A1 - Rotta, Randolf A1 - Noack, Andreas T1 - Multilevel local search algorithms for modularity clusterin T2 - Journal on Experimental Algorithmics Y1 - 2011 SN - 1084-6654 VL - 16 IS - 2 ER - TY - GEN A1 - Rotta, Randolf A1 - Prescher, Thomas A1 - Traue, Jana A1 - Nolte, Jörg T1 - Data Sharing Mechanisms for Parallel Graph Algorithms on the Intel SCC T2 - MARC Symposium at ONERA'2012, July 19th–20th 2012, Toulouse, Frankreich Y1 - 2012 UR - http://hal.archives-ouvertes.fr/hal-00718993 SN - 978-2-7257-0016-8 N1 - Best Paper Award 2012 SP - 13 EP - 18 ER - TY - GEN A1 - Rotta, Randolf A1 - Büchner, Steffen A1 - Nolte, Jörg T1 - Middleware for Many-Cores - Why It Is Needed and What Functionality It Should Provide T2 - 4th USENIX Workshop on Hot Topics in Parallelism (HotPar '12), Berkeley, 2012 N2 - Today's multi-cores and future many-cores are NUMA architectures with complex cache hierarchies and multiple memory channels. Depending on the topologies of these memory networks we find everything from true data sharing with shared caches to distributed memory architectures which just pretend to be physical shared memory systems. In fact, most many-cores are hybrid systems that exhibit the characteristics of both distributed systems and SMPs. In this paper we argue in favor of middleware platforms for many-cores. We will discuss the needed functionality in contrast to common distributed system middleware and present micro benchmarks on several architectures to substantiate our claims. Y1 - 2012 UR - https://www.usenix.org/conference/hotpar12/tech-schedule/poster-session ER - TY - GEN A1 - Rotta, Randolf A1 - Prescher, Thomas A1 - Traue, Jana A1 - Nolte, Jörg T1 - In-Memory Communication Mechanisms for Many-Cores – Experiences with the Intel SCC T2 - TACC-Intel Highly Parallel Computing Symposium (TIHPCS), Austin/Texas, 2012 N2 - Many-core processors combine fast on-chip communication with access to large amounts of shared memory. This makes it possible to exploit the benefits of distributed as well as shared memory programming models within single parallel algorithms. While large amounts of data can be shared in the memory and caches, coordinating the activities of hundreds of cores relies on cross core communication mechanisms with ultra low latency for very small messages. In this paper we discuss two communication protocols for the Intel SCC and compare them to the MPI implementation of the SCC. Our micro-benchmark results underline that special purpose protocols for small messages make much finer levels of parallelism possible than general purpose message passing systems. Index Terms—many-core, message passing, shared memory Y1 - 2012 UR - http://www.tacc.utexas.edu/documents/13601/4234acca-2171-4465-aa48-7592d5e577f9 UR - http://www.tacc.utexas.edu/documents/13601/06d702ab-3f48-4942-9b07-2fbd880d4310 UR - http://www.tacc.utexas.edu/ti-hpcs12 ER - TY - GEN A1 - Rotta, Randolf A1 - Traue, Jana A1 - Prescher, Thomas A1 - Nolte, Jörg T1 - Interrupt-Driven Cross-Core Invocation Mechanisms on the Intel SCC T2 - Proceedings of the Many-core Applications Research Community (MARC) Symposium at RWTH Aachen University 2012 N2 - On many-core processors, both operating system kernels and bare metal applications need efficient cross-core coordination and communication. Although explicit shared- memory programming and message passing might provide the best performance, they also limit the system’s control over scheduling. In contrast, interrupt-driven cross-core invocations provide universal coordination mechanisms that also enable preemptive operations across cores. This paper surveys cross- core invocation mechanisms and their usability with respect to prevalent coordination scenarios. We integrated some of these mechanisms into a bare-metal environment for the Intel SCC pro- cessor and will discuss implementation aspects of the interrupt- driven invocations. In conclusion, such invocation mechanisms provide an expressive platform for future operating systems kernels and bare-metal applications. KW - many-core KW - remote invocations KW - bare-metal Y1 - 2012 SN - 978-3-00-039545-1 SP - 1 EP - 6 PB - Technische Hochschule CY - Aachen ER - TY - GEN A1 - Nürnberger, Stefan A1 - Rotta, Randolf A1 - Drescher, Gabor A1 - Danner, Daniel A1 - Nolte, Jörg T1 - Diamond Rings: Acknowledged Event Propagation in Many-Core Processors T2 - Euro-Par 2015: Parallel Processing Workshops, Vienna, 2015 N2 - Hardware and software consistency protocols rely on global observability of consistency events. Acknowledged broadcast is an obvious choice to propagate these events. This paper presents a generalized ring topology for parallel event propagation with acknowledged delivery. Implementations for various many-core architectures show increased performance over conventional approaches. Therefore, diamond rings are a prime candidate for implementations of distributed memory models. Y1 - 2015 UR - http://link.springer.com/chapter/10.1007%2F978-3-319-27308-2_58 SN - 978-3-319-27308-2 U6 - https://doi.org/10.1007/978-3-319-27308-2_58 SP - 722 EP - 733 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Nürnberger, Stefan A1 - Drescher, Gabor A1 - Rotta, Randolf A1 - Nolte, Jörg A1 - Schröder-Preikschat, Wolfgang T1 - Shared Memory in the Many-Core Age T2 - Euro-Par 2014: Parallel Processing Workshops, Porto, 2014 N2 - With the evolution toward fast networks of many-core processors, the design assumptions at the basis of software-level distributed shared memory (DSM) systems change considerably. But efficient DSMs are needed because they can significantly simplify the implementation of complex distributed algorithms. This paper discusses implications of the many-core evolution and derives a set of reusable elementary operations for future software DSMs. These elementary operations will help in exploring and evaluating new memory models and consistency protocols. Y1 - 2014 UR - http://link.springer.com/chapter/10.1007%2F978-3-319-14313-2_30 SN - 978-3-319-14312-5 U6 - https://doi.org/10.1007/978-3-319-14313-2_30 SP - 351 EP - 362 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Rotta, Randolf A1 - Nolte, Jörg A1 - Nikolov, Vladimir A1 - Schubert, Lutz A1 - Bonfert, Stefan A1 - Wesner, Stefan T1 - MyThOS — Scalable OS Design for Extremely Parallel Applications T2 - 2016 Intl IEEE Conferences on Ubiquitous Intelligence Computing, Advanced and Trusted Computing, Scalable Computing and Communications, Cloud and Big Data Computing, Internet of People, and Smart World Congress, 18-21 July 2016 N2 - Many-core architectures trade single-thread performance for a larger number of cores. Scalable throughput can be attained only by a high degree of parallelism, minimized synchronization. Whilst this is achievable for many applications, the operating system still introduces bottlenecks through non-local sharing, synchronization,, message passing. A particular challenge for highly dynamic applications, for example invasive HPC applications, elastic compute clouds, is the management of short-living application threads, processes. This paper discusses OS architecture choices based on microkernel, multikernel, distributed systems designs, our development experience in the context of the MyThOS project. Initial experiments show a much faster thread creation, activation compared to monolithic systems like Linux while providing a more flexible protection, threading model that is better suited for dynamic scenarios. However, despite significant progress in the overall domain of operating systems, the design space for scalable many-core operating systems is yet to be fully explored. Y1 - 2016 SN - 978-1-5090-2771-2 U6 - https://doi.org/10.1109/UIC-ATC-ScalCom-CBDCom-IoP-SmartWorld.2016.0179 SP - 1165 EP - 1172 PB - IEEE CY - Piscataway, NJ ER - TY - GEN A1 - Rotta, Randolf A1 - Kuban, Robert A1 - Schöps, Mark Simon A1 - Nolte, Jörg T1 - Dealing with Layers of Obfuscation in pseudo-Uniform Memory Architectures T2 - Euro-Par 2016: Parallel Processing Workshops, Euro-Par 2016 International Workshops, Grenoble, France, August 24-26, 2016 N2 - Pseudo-Uniform Memory Architectures hide the memory's throughput bottlenecks and the network's latency differences in order to provide near-peak average throughput for computations on large datasets. This obviates the need for application-level partitioning and load balancing between NUMA domains but the performance of cross-core communication still depends on the actual placement of the involved variables and cores, which can result in significant variation within applications and between application runs. This paper analyses the pseudo-uniform memory latency on the Intel Xeon Phi Knights Corner processor, derives strategies for the optimised placement of important variables, and discusses the role of localised coordination in pUMA systems. For example, a basic cache line ping-pong benchmark showed a 3x speedup between adjacent cores. Therefore, pUMA systems combined with support for controlled placement of small datasets are an interesting option when processor-wide load balancing is difficult while localised coordination is feasible. Y1 - 2016 SN - 978-3-319-58942-8 SN - 978-3-319-58943-5 U6 - https://doi.org/10.1007/978-3-319-58943-5_55 SP - 685 EP - 696 PB - Springer International Publishing CY - Cham ER - TY - GEN A1 - Kuban, Robert A1 - Rotta, Randolf A1 - Nolte, Jörg ED - Heras, Dora B. ED - Bougé, Luc T1 - Help Your Busy Neighbors: Dynamic Multicasts over Static Topologies T2 - Euro-Par 2017: Parallel Processing Workshops KW - multicast KW - shared memory KW - many-core KW - TLB shootdown Y1 - 2018 SN - 978-3-319-75177-1 SN - 978-3-319-75178-8 U6 - https://doi.org/10.1007/978-3-319-75178-8_51 N1 - viele weitere Herausgeber SP - 636 EP - 657 PB - Springer CY - Cham ER - TY - GEN A1 - Rotta, Randolf A1 - Segabinazzi Ferreira, Raphael A1 - Nolte, Jörg T1 - Real-time dynamic hardware reconfiguration for processors with redundant functional units T2 - Proceedings of the 2020 IEEE 23rd International Symposium on Real-Time Distributed Computing (ISORC) N2 - The tiny logic elements in modern integrated circuits increase the rate of transient failures significantly. Therefore, redundancy on various levels is necessary to retain reliability. However, for mixed-criticality scenarios, the typical processor designs offer either too little fault-tolerance or too much redundancy for one part of the applications. Amongst others, we specifically address redundant processor internal functional units (FU) to cope with transient errors and support wear leveling. A real-time operating system (RTOS) was extended to control our prototypical hardware platform and, since it can be configured deterministically within few clock cycles, we are able to reconfigure the FUs dynamically, at process switching time, according to the specified critically of the running processes. Our mechanisms were integrated into the Plasma processor and the Plasma-RTOS. With few changes to the original software code, it was, for example, possible to quickly change from fault-detecting to fault-correcting modes of the processor on demand. KW - Mixed-criticality; Modular redundancy; Reconfiguration; Run-Time Y1 - 2020 SN - 978-1-7281-6958-3 U6 - https://doi.org/10.1109/ISORC49007.2020.00035 SN - 2375-5261 PB - Institute of Electrical and Electronics Engineers Inc. (IEEE) CY - Nashville, TN, USA ER - TY - GEN A1 - Rotta, Randolf A1 - Mykytyn, Pavlo T1 - Secure Multi-hop Telemetry Broadcasts for UAV Swarm Communication T2 - 20. GI/ITG KuVS Fachgespräch Sensornetze (FGSN 2023) N2 - Unmanned Aerial Vehicles (UAVs) are evolving as adaptable platforms for a wide range of applications such as precise inspections, emergency response, and remote sensing. Autonomous UAV swarms require efficient and stable communication during deployment for a successful mission execution. For instance, the periodic exchange of telemetry data between all swarm members provides the foundation for formation flight and collision avoidance. However, due to the mobility of the vehicles and instability of wireless transmissions, maintaining a secure and reliable all-to-all communication remains challenging. This paper investigates encrypted and authenticated multi-hop broadcast communication based on the transmission of custom IEEE 802.11 Wi-Fi data frames. KW - Unmanned Aerial Vehicles, Multi-hop Networks, Vehicular Networks, Swarm Flight Y1 - 2023 U6 - https://doi.org/10.48550/arXiv.2401.11915 SP - 13 EP - 14 ER - TY - GEN A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Karnapke, Reinhardt A1 - Nolte, Jörg T1 - Assessing the Feasibility of Combined BLE and Wi-Fi Communication for High Data Sensing Applications T2 - EWSN '23: Proceedings of the 2023 International Conference on Embedded Wireless Systems and Networks N2 - Advanced sensors generate more data than can be transmitted using classic battery-powered wireless sensor networks. While using Wi-Fi would provide plenty of throughput, the receivers are energy hungry and, thus, the radio time needs to be reduced. Previous research suggests to combine Wi-Fi with low-power technologies such as BLE for an energy efficient coordination of the Wi-Fi radios. Existing approaches focus on individual point-to-point routes whereas certain applications require concurrent transmissions. We evaluated the combination of BLE and Wi-Fi on the ESP32-S3 multi-radio microcontroller through detailed energy and throughput measurements. The results show that established BLE connections allow to activateWi-Fi quickly on-demand; the energy efficiency of the data transmission is significantly improved over previous works but the BLE connection setup is prohibitively slow. While the combination of BLE and Wi-Fi provides high throughput with good energy efficiency, careful design of the BLE-based signalling protocol is necessary to also achieve low latency. Y1 - 2023 U6 - https://doi.org/10.5555/3639940.3639948 SP - 56 EP - 59 PB - Association for Computing Machinery CY - New York ER - TY - GEN A1 - Nattke, Matthias A1 - Rotta, Randolf A1 - Natarov, Roman A1 - Archila, Oscar A1 - Mykytyn, Pavlo T1 - Precise sensors for localization in the drone swarm T2 - Proceedings iCCC2024 - iCampµs Cottbus Conference, 2024-05-14 - 2024-05-16, Cottbus N2 - Drones can be connected as a swarm to precisely monitor large agricultural areas and manage them more sustainable. They test sensor technology in real environments and solve complex tasks faster. Key aspects include accurate localization, reliable communication, and dynamic flight control. The localization accuracy of RTK-GNSS-enabled system, which includes GPS, GLONASS, GALILEO positioning systems is compared with Ultra-Wideband (UWB) one. The UPWARDS communication hub is presented as a processing and connection point across swarm agents. This controller also incorporates collision avoidance features and testing of evasion strategies. KW - ROS KW - GNSS KW - UWB KW - communication hub KW - UAV swarm Y1 - 2024 UR - https://www.ama-science.org/proceedings/details/4724 SN - 978-3-910600-00-3 U6 - https://doi.org/10.5162/iCCC2024/P16 VL - 2024 SP - 166 EP - 169 PB - AMA ER - TY - CHAP A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Nolte, Jörg T1 - P2 - VibroMote: Energy efficient Vibration Monitoring for Railway tracks and Bridges T2 - iCCC2024 - iCampµs Cottbus Conference 2024-05-14 - 2024-05-16 N2 - Filtering, storing, and transmitting measurements of high-resolution sensors within a limited energy budget is challenging. For instance, a 3-axis MEMS acceleration sensor for structural condition monitoring and predictive maintenance generates up to 160 kB/s at a sampling rate of 26.6 kHz. This paper discusses the design space with focus on solar harvesting solutions. VibroMote is an energy efficient sensor node that combines a multi-radio micro-controller, an ultra-low power co-processor with persistent memory, a solar harvester, and multiple energy storage options. This enables prototyping of solar-powered long-term data acquisition, in-node processing, and wireless networking for high-resolution sensors. KW - structural condition monitoring KW - predictive maintenance KW - energy efficiency KW - solar harvesting Y1 - 2024 SN - 978-3-910600-00-3 U6 - https://doi.org/10.5162/iCCC2024/P2 SP - 123 EP - 126 PB - AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany ER - TY - GEN A1 - Rotta, Randolf A1 - Chatharajupalli, Navya Sneha A1 - Naumann, Billy A1 - Schulz, Julius A1 - Karnapke, Reinhardt A1 - Werner, Matthias A1 - Nolte, Jörg T1 - Demo: B.A.T.M.A.N. mesh routing on ultra low-power IEEE 802.11 modules T2 - 2024 IEEE 49th Conference on Local Computer Networks (LCN) N2 - When implementing multi-hop mesh network protocols, efficient direct communication, route discovery, and route repair are crucial to achieve high network throughput. To our knowledge, there is no open mesh routing protocol available for ultra low power IEEE 802.11 modules. Previous work relied on single board computers like Raspberry Pi. We implemented the B.A.T.M.A.N. mesh protocol on the popular Espressif ESP32 along with a novel hybrid rate adaptation for the selection of efficient routes. In this demo we showcase challenges and solutions related to the implementation on ESP32 and how the hybrid rate adaptation improves end-to-end throughput. KW - ad-hoc networks KW - mesh networks KW - low power electronics KW - throughput Y1 - 2024 SN - 979-8-3503-8800-8 U6 - https://doi.org/10.1109/LCN60385.2024.10639789 SN - 2832-1421 PB - IEEE ER - TY - GEN A1 - Rotta, Randolf A1 - Schulz, Julius A1 - Naumann, Billy A1 - Chatharajupalli, Navya Sneha A1 - Nolte, Jörg A1 - Werner, Matthias T1 - B.A.T.M.A.N. Mesh Networking on ESP32’s 802.11 T2 - 2024 IEEE 49th Conference on Local Computer Networks (LCN) N2 - Mesh routing protocols are widely used in IoT and sensor networks. In recent years, the ESP32 Wi-Fi/BLE SoC became popular for prototyping IoT applications. However, the existing mesh networks for this platform lack efficient node to node communication, fast route discovery and repair, and energy efficiency. This paper addresses the formation of IEEE 802.11 based ad-hoc mesh networks without the delays inflicted by the Station to Access Point association protocol. We implemented the B.A.T.M.A.N. protocol on top of the ESP32 Wi-Fi MAC interface and integrated it into the LwIP network stack. The performance evaluation with respect to UDP/IP and TCP/IP end-to-end throughput shows the general usefulness but also identifies bottlenecks caused by limitations of the existing MAC interface. Overall, this opens an interesting opportunity for research on mesh protocols by providing a simpler platform than full featured Wi-Fi routers; and for wireless IoT applications by providing higher throughput than subGHz and BLE technologies. KW - wireless communication KW - mesh networks KW - wireless sensor networks KW - routing protocols Y1 - 2024 SN - 979-8-3503-8800-8 U6 - https://doi.org/10.1109/LCN60385.2024.10639698 SN - 2832-1421 SN - 2831-7742 SP - 1 EP - 7 PB - IEEE ER - TY - GEN A1 - Shahin, Keyvan A1 - Rotta, Randolf A1 - Archila, Oscar A1 - Mykytyn, Pavlo A1 - Nattke, Matthias A1 - Reichenbach, Marc A1 - Nolte, Jörg A1 - Natarov, Roman T1 - A Modular Communication Architecture for Adaptive UAV Swarms T2 - 2023 IEEE International Conference on Omni-layer Intelligent Systems (COINS) N2 - Small Unmanned Aerial Vehicles (UAVs) have vast application potential from industrial logistics and disaster monitoring to smart farming, for example, to create maps with Normalized Difference Vegetation Index (NDVI) cameras and AI-based image classification or the precision spot application of fertilizers. Operating multiple UAVs in parallel, including those with different specializations, enables efficient coverage of large areas. While existing research focused mainly on predefined flight formations for swarms or autonomous missions for single UAVs, the focus of this work is on multiple UAVs with individually adaptable missions. We derive communication system requirements from swarm coordination algorithms and present a respective design. The resulting modular architecture enables future research on autonomous adaptive UAV swarms and their use as flying sensor platforms. Y1 - 2023 SN - 979-8-3503-4647-3 SN - 979-8-3503-4648-0 U6 - https://doi.org/10.1109/COINS57856.2023.10189245 PB - IEEE CY - Berlin ER -