Iakovos Mavroidis
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Research Interests
Iakovos Mavroidis has a total of 96 co-authors. Here are the top co-authors by number of shared publications:
Ioannis Papaefstathiou
7 shared publications- Aggelos Ioannou
Lawrence Berkeley National Laboratory, Berkeley, CA, USA
4 shared publications Luciano Lavagno
Telecommunication Systems Institute (TSI), Technical University of Crete
4 shared publicationsVassilis Papaefstathiou
4 shared publicationsAggelos Ioannou
Foundation for Research and Technology Hellas, Greece
2 shared publications- Chloe Alverti
University of Illinois Urbana-Champaign, Urbana-Champaign, Illinois, USA
2 shared publications
Latest Publications
- Open Access
- 12 April 2025
- Published by Association for Computing Machinery (ACM) in ACM Transactions on Reconfigurable Technology and Systems
- Vol. 18 (2) , 1-34
The ExaNeSt Prototype: Evaluation of Efficient HPC Communication Hardware in an ARM-based Multi-FPGA Rack
We present and evaluate the ExaNeSt prototype, which compactly packages 128 Xilinx ZU9EG MPSoCs, two TBytes of DRAM, and eight TBytes of SSD into a liquid-cooled rack, using a custom interconnection hardware based on 10 GB/s links. We developed this testbed in 2016–2019 in order to leverage the flexibility of FPGAs for experimenting with efficient hardware support for HPC communication among tens of thousands of processors and accelerators in the quest toward Exascale systems and beyond. In the years since then, we carefully studied this system, and we present our key design choices and insights resulting from our measurement and analysis. We developed this testbed, from architecture to the PCBs and the run-time software, within the ExaNeSt project. It is fully operational in configurations with up to 8 × 4 × 4 MPSoC nodes. It achieves high density through tight board design, while also leveraging state-of-the-art liquid cooling technology. In this article, we present a thorough architectural analysis, along with important aspects of our infrastructure development. Our custom interconnect includes a low-cost low-latency network interface, offering user-level, zero-copy RDMA, which we coupled with the ARMv8 processors in the MPSoCs. We further developed the corresponding runtimes that allow us to test real MPI applications on the large-scale testbed. We evaluated our platform through MPI microbenchmarks, mini application, and full MPI applications. Single-hop, one-way latency is 1.3 μs; approximately 0.47 μs out of these are attributed to network interface and the user-space library that exposes its functionality to the runtime. Latency over longer paths increases as expected, reaching 2.55 μs for a five-hop path. Bandwidth tests show that, for single-hop, link utilization reaches \(82\%\) of the theoretical capacity. Microbenchmarks based on MPI collectives reveal that broadcast latency scales as expected when the number of participating ranks increases. We also implemented a custom MPI_Allreduce accelerator in the network interface, which reduces the latency of such collectives by up to \(88\%\) . We assess performance scaling through weak and strong scaling tests for HPCG, LAMMPS, and the miniFE mini application; for all these tests, parallelization efficiency is at least \(69\%\) , or better.- 12 April 2025
- Published by Association for Computing Machinery (ACM) in ACM Transactions on Reconfigurable Technology and Systems
- Vol. 18 (2) , 1-34
Open AccessThe ExaNeSt Prototype: Evaluation of Efficient HPC Communication Hardware in an ARM-based Multi-FPGA Rack
We present and evaluate the ExaNeSt prototype, which compactly packages 128 Xilinx ZU9EG MPSoCs, two TBytes of DRAM, and eight TBytes of SSD into a liquid-cooled rack, using a custom interconnection hardware based on 10 GB/s links. We developed this testbed in 2016–2019 in order to leverage the flexibility of FPGAs for experimenting with efficient hardware support for HPC communication among tens of thousands of processors and accelerators in the quest toward Exascale systems and beyond. In the years since then, we carefully studied this system, and we present our key design choices and insights resulting from our measurement and analysis. We developed this testbed, from architecture to the PCBs and the run-time software, within the ExaNeSt project. It is fully operational in configurations with up to 8 × 4 × 4 MPSoC nodes. It achieves high density through tight board design, while also leveraging state-of-the-art liquid cooling technology. In this article, we present a thorough architectural analysis, along with important aspects of our infrastructure development. Our custom interconnect includes a low-cost low-latency network interface, offering user-level, zero-copy RDMA, which we coupled with the ARMv8 processors in the MPSoCs. We further developed the corresponding runtimes that allow us to test real MPI applications on the large-scale testbed. We evaluated our platform through MPI microbenchmarks, mini application, and full MPI applications. Single-hop, one-way latency is 1.3 μs; approximately 0.47 μs out of these are attributed to network interface and the user-space library that exposes its functionality to the runtime. Latency over longer paths increases as expected, reaching 2.55 μs for a five-hop path. Bandwidth tests show that, for single-hop, link utilization reaches \(82\%\) of the theoretical capacity. Microbenchmarks based on MPI collectives reveal that broadcast latency scales as expected when the number of participating ranks increases. We also implemented a custom MPI_Allreduce accelerator in the network interface, which reduces the latency of such collectives by up to \(88\%\) . We assess performance scaling through weak and strong scaling tests for HPCG, LAMMPS, and the miniFE mini application; for all these tests, parallelization efficiency is at least \(69\%\) , or better. - Open Access
The ExaNeSt Prototype: Evaluation of Efficient HPC Communication Hardware in an ARM-based Multi-FPGA Rack
We present and evaluate the ExaNeSt Prototype, a liquid-cooled rack prototype consisting of 256 Xilinx ZU9EG MPSoCs, 4 TBytes of DRAM, 16 TBytes of SSD, and configurable interconnection 10-Gbps hardware. We developed this testbed in 2016-2019 to validate the flexibility of FPGAs for experimenting with efficient hardware support for HPC communication among tens of thousands of processors and accelerators in the quest towards Exascale systems and beyond. We present our key design choices reagrding overall system architecture, PCBs and runtime software, and summarize insights resulting from measurement and analysis. Of particular note, our custom interconnect includes a low-cost low-latency network interface, offering user-level zero-copy RDMA, which we have tightly coupled with the ARMv8 processors in the MPSoCs. We have developed a system software runtime on top of these features, and have been able to run MPI. We have evaluated our testbed through MPI microbenchmarks, mini, and full MPI applications. Single hop, one way latency is $1.3$~$μ$s; approximately $0.47$~$μ$s out of these are attributed to network interface and the user-space library that exposes its functionality to the runtime. Latency over longer paths increases as expected, reaching $2.55$~$μ$s for a five-hop path. Bandwidth tests show that, for a single hop, link utilization reaches $82\%$ of the theoretical capacity. Microbenchmarks based on MPI collectives reveal that broadcast latency scales as expected when the number of participating ranks increases. We also implemented a custom Allreduce accelerator in the network interface, which reduces the latency of such collectives by up to $88\%$. We assess performance scaling through weak and strong scaling tests for HPCG, LAMMPS, and the miniFE mini application; for all these tests, parallelization efficiency is at least $69\%$, or better.Open AccessThe ExaNeSt Prototype: Evaluation of Efficient HPC Communication Hardware in an ARM-based Multi-FPGA Rack
We present and evaluate the ExaNeSt Prototype, a liquid-cooled rack prototype consisting of 256 Xilinx ZU9EG MPSoCs, 4 TBytes of DRAM, 16 TBytes of SSD, and configurable interconnection 10-Gbps hardware. We developed this testbed in 2016-2019 to validate the flexibility of FPGAs for experimenting with efficient hardware support for HPC communication among tens of thousands of processors and accelerators in the quest towards Exascale systems and beyond. We present our key design choices reagrding overall system architecture, PCBs and runtime software, and summarize insights resulting from measurement and analysis. Of particular note, our custom interconnect includes a low-cost low-latency network interface, offering user-level zero-copy RDMA, which we have tightly coupled with the ARMv8 processors in the MPSoCs. We have developed a system software runtime on top of these features, and have been able to run MPI. We have evaluated our testbed through MPI microbenchmarks, mini, and full MPI applications. Single hop, one way latency is $1.3$~$μ$s; approximately $0.47$~$μ$s out of these are attributed to network interface and the user-space library that exposes its functionality to the runtime. Latency over longer paths increases as expected, reaching $2.55$~$μ$s for a five-hop path. Bandwidth tests show that, for a single hop, link utilization reaches $82\%$ of the theoretical capacity. Microbenchmarks based on MPI collectives reveal that broadcast latency scales as expected when the number of participating ranks increases. We also implemented a custom Allreduce accelerator in the network interface, which reduces the latency of such collectives by up to $88\%$. We assess performance scaling through weak and strong scaling tests for HPCG, LAMMPS, and the miniFE mini application; for all these tests, parallelization efficiency is at least $69\%$, or better. - Open Access
- 9 May 2023
- Published by Association for Computing Machinery (ACM)
- p. 304-308
Early Results of Mapping Industrial Applications on Heterogeneous HPC Systems
The OPTIMA project aims to port and optimize industrial applications and a set of open-source libraries into two novel FPGA-populated HPC systems. Target applications are from the domains of robotics simulation, underground analysis and computational fluid dynamics (CFD), where data processing is based on differential equations, matrix-matrix and matrix-vector operations. Moreover, the OPTIMA OPen Source (OOPS) library will support basic linear algebraic operations, sparse matrix-vector arithmetic, as well as computer-aided engineering (CAE) solvers. The OPTIMA target platforms are JUMAX, an HPC system that couples an AMD Epyc Server with Maxeler FPGA-based Dataflow Engines (DFEs), and server class machines with Alveo FPGA cards installed. Experimental results show that performance on robotic simulation can be enhanced up to 1.2x, and CFD calculations up to 4.7x. Finally, BLAS L1 routines are improved up to 7x, with a performance-per-Watt ratio boost of more than 40x compared to multi-threaded software routines from the Intel Math Kernel Library (MKL) suite when executed on an Intel Xeon server-class machine.
- 9 May 2023
- Published by Association for Computing Machinery (ACM)
- p. 304-308
Open AccessEarly Results of Mapping Industrial Applications on Heterogeneous HPC Systems
The OPTIMA project aims to port and optimize industrial applications and a set of open-source libraries into two novel FPGA-populated HPC systems. Target applications are from the domains of robotics simulation, underground analysis and computational fluid dynamics (CFD), where data processing is based on differential equations, matrix-matrix and matrix-vector operations. Moreover, the OPTIMA OPen Source (OOPS) library will support basic linear algebraic operations, sparse matrix-vector arithmetic, as well as computer-aided engineering (CAE) solvers. The OPTIMA target platforms are JUMAX, an HPC system that couples an AMD Epyc Server with Maxeler FPGA-based Dataflow Engines (DFEs), and server class machines with Alveo FPGA cards installed. Experimental results show that performance on robotic simulation can be enhanced up to 1.2x, and CFD calculations up to 4.7x. Finally, BLAS L1 routines are improved up to 7x, with a performance-per-Watt ratio boost of more than 40x compared to multi-threaded software routines from the Intel Math Kernel Library (MKL) suite when executed on an Intel Xeon server-class machine.
- Open Access
- 24 September 2022
- Published by MDPI AG in Electronics
- Vol. 11 (19) , 3039
Preconditioned Conjugate Gradient Acceleration on FPGA-Based Platforms
Reconfigurable computing can significantly improve the performance and energy efficiency of many applications. However, FPGA-based chips are evolving rapidly, increasing the difficulty of evaluating the impact of new capabilities such as HBM and high-speed links. In this paper, a real-world application was implemented on different FPGAs in order to better understand the new capabilities of modern FPGAs and how new FPGA technology improves performance and scalability. The aforementioned application was the preconditioned conjugate gradient (PCG) method that is utilized in underground analysis. The implementation was done on four different FPGAs, including an MPSoC, taking into account each platform’s characteristics. The results show that today’s FPGA-based chips offer eight times better performance on a memory-bound problem than 5-year-old FPGAs, as they incorporate HBM and can operate at higher clock frequencies.
- 24 September 2022
- Published by MDPI AG in Electronics
- Vol. 11 (19) , 3039
Open AccessPreconditioned Conjugate Gradient Acceleration on FPGA-Based Platforms
Reconfigurable computing can significantly improve the performance and energy efficiency of many applications. However, FPGA-based chips are evolving rapidly, increasing the difficulty of evaluating the impact of new capabilities such as HBM and high-speed links. In this paper, a real-world application was implemented on different FPGAs in order to better understand the new capabilities of modern FPGAs and how new FPGA technology improves performance and scalability. The aforementioned application was the preconditioned conjugate gradient (PCG) method that is utilized in underground analysis. The implementation was done on four different FPGAs, including an MPSoC, taking into account each platform’s characteristics. The results show that today’s FPGA-based chips offer eight times better performance on a memory-bound problem than 5-year-old FPGAs, as they incorporate HBM and can operate at higher clock frequencies.
- 1 November 2019
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- p. 34-41
Implementation and Impact of an Ultra-Compact Multi-FPGA Board for Large System Prototyping
Efficient prototyping of a large complex system can be significantly facilitated by the use of a flexible and versatile physical platform where both new hardware and software components can readily be implemented and tightly integrated in a timely manner. Towards this end, we have developed the 120 130 mm QFDB board and associated firmware, including the system software environment. We developed a large system based on this advanced dense and modular building block. The QFDB features 4 interconnected Xilinx Zynq Ultrascale+ devices, each one consisting of an ARM-based subsystem tightly coupled with reconfigurable logic. Each Zynq Ultrascale+ is connected to 16 GB of DDR4 memory. In addition, one Zynq provides storage through an M.2 Solid State Disk (SSD). In this paper, we present the design and the implementation of this board, as well as the software environment for board operation. Moreover, we describe a 10 Gb Ethernet communication infrastructure for interconnecting multiple boards together. Finally, we highlight the impact of this board on a number of ongoing research activities that leverage the QFDB versatility, both as a largescale prototyping system for HPC solutions, and as a host for the development of FPGA integration techniques.
- 1 November 2019
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- p. 34-41
Implementation and Impact of an Ultra-Compact Multi-FPGA Board for Large System Prototyping
Efficient prototyping of a large complex system can be significantly facilitated by the use of a flexible and versatile physical platform where both new hardware and software components can readily be implemented and tightly integrated in a timely manner. Towards this end, we have developed the 120 130 mm QFDB board and associated firmware, including the system software environment. We developed a large system based on this advanced dense and modular building block. The QFDB features 4 interconnected Xilinx Zynq Ultrascale+ devices, each one consisting of an ARM-based subsystem tightly coupled with reconfigurable logic. Each Zynq Ultrascale+ is connected to 16 GB of DDR4 memory. In addition, one Zynq provides storage through an M.2 Solid State Disk (SSD). In this paper, we present the design and the implementation of this board, as well as the software environment for board operation. Moreover, we describe a 10 Gb Ethernet communication infrastructure for interconnecting multiple boards together. Finally, we highlight the impact of this board on a number of ongoing research activities that leverage the QFDB versatility, both as a largescale prototyping system for HPC solutions, and as a host for the development of FPGA integration techniques.
- 10 September 2019
- Published by Taylor & Francis
- p. 153-189
A Novel Framework for Utilising Multi-FPGAs in HPC Systems
This chapter presents the technology developed in the context of European project ECOSCALE. It aims at contributing to the effort for a state-of-the-art platform that can satisfactorily serve applications in the context of High Performance Computing (HPC). ECOSCALE is a platform that comprises of both a novel software framework that allows users to introduce their applications described in OpenCL as well as an architecture that utilises reconfigurable hardware in order to execute at high speeds computationally-intensive tasks. The ECOSCALE platform proposes a framework with a number of functional and technological layers. ECOSCALE introduces the Worker that is the processing unit of its technology. It is effectively a single ECOSCALE FPGA featuring all elements required for a single computational node, i.e. a processing system, memory and reconfigurable logic. The computationally-intensive tasks are meant to be implemented within the reconfigurable section of the FPGA in what are referred to as accelerator modules. Furthermore, the complete ECOSCALE prototype is going to be comprised of 64 FPGAs (Workers), which thank to ECOSCALE's UNILOGIC technology, will be available for exploitation by any given application in a seamless and transparent manner. An added benefit from using FPGA technology is the potential for a low-power HPC system.
- 10 September 2019
- Published by Taylor & Francis
- p. 153-189
A Novel Framework for Utilising Multi-FPGAs in HPC Systems
This chapter presents the technology developed in the context of European project ECOSCALE. It aims at contributing to the effort for a state-of-the-art platform that can satisfactorily serve applications in the context of High Performance Computing (HPC). ECOSCALE is a platform that comprises of both a novel software framework that allows users to introduce their applications described in OpenCL as well as an architecture that utilises reconfigurable hardware in order to execute at high speeds computationally-intensive tasks. The ECOSCALE platform proposes a framework with a number of functional and technological layers. ECOSCALE introduces the Worker that is the processing unit of its technology. It is effectively a single ECOSCALE FPGA featuring all elements required for a single computational node, i.e. a processing system, memory and reconfigurable logic. The computationally-intensive tasks are meant to be implemented within the reconfigurable section of the FPGA in what are referred to as accelerator modules. Furthermore, the complete ECOSCALE prototype is going to be comprised of 64 FPGAs (Workers), which thank to ECOSCALE's UNILOGIC technology, will be available for exploitation by any given application in a seamless and transparent manner. An added benefit from using FPGA technology is the potential for a low-power HPC system.
- 8 August 2019
- Published by Springer Nature
- p. 442-454
Optimized FPGA Implementation of a Compute-Intensive Oil Reservoir Simulation Algorithm
- 8 August 2019
- Published by Springer Nature
- p. 442-454
Optimized FPGA Implementation of a Compute-Intensive Oil Reservoir Simulation Algorithm
- 22 August 2018
- Published by Springer Nature
- p. 199-213
Energy-Efficient Heterogeneous Computing at exaSCALE—ECOSCALE
- 22 August 2018
- Published by Springer Nature
- p. 199-213
Energy-Efficient Heterogeneous Computing at exaSCALE—ECOSCALE
- 8 April 2018
- Published by Springer Nature
- p. 724-736
HLS Algorithmic Explorations for HPC Execution on Reconfigurable Hardware - ECOSCALE
- 8 April 2018
- Published by Springer Nature
- p. 724-736
HLS Algorithmic Explorations for HPC Execution on Reconfigurable Hardware - ECOSCALE
- Open Access
- 1 January 2016
- Published by Research Publishing Services
- p. 696-701
ECOSCALE: Reconfigurable Computing and Runtime System for Future Exascale Systems
In order to reach exascale performance, current HPC systems need to be improved. Simple hardware scaling is not a feasible solution due to the increasing utility costs and power consumption limitations. Apart from improvements in implementation technology, what is needed is to refine the HPC application development flow as well as the system architecture of future HPC systems. ECOSCALE tackles these challenges by proposing a scalable programming environment and architecture, aiming to substantially reduce energy consumption as well as data traffic and latency. ECOSCALE introduces a novel heterogeneous energy-efficient hierarchical architecture, as well as a hybrid many-core+OpenCL programming environment and runtime system. The ECOSCALE approach is hierarchical and is expected to scale well by partitioning the physical system into multiple independent Workers (i.e. compute nodes). Workers are interconnected in a tree-like fashion and define a contiguous global address space that can be viewed either as a set of partitions in a Partitioned Global Address Space (PGAS), or as a set of nodes hierarchically interconnected via an MPI protocol. To further increase energy efficiency, as well as to provide resilience, the Workers employ reconfigurable accelerators mapped into the virtual address space utilizing a dual stage System Memory Management Unit with coherent memory access. The architecture supports shared partitioned reconfigurable resources accessed by any Worker in a PGAS partition, as well as automated hardware synthesis of these resources from an OpenCL-based programming model.
- 1 January 2016
- Published by Research Publishing Services
- p. 696-701
Open AccessECOSCALE: Reconfigurable Computing and Runtime System for Future Exascale Systems
In order to reach exascale performance, current HPC systems need to be improved. Simple hardware scaling is not a feasible solution due to the increasing utility costs and power consumption limitations. Apart from improvements in implementation technology, what is needed is to refine the HPC application development flow as well as the system architecture of future HPC systems. ECOSCALE tackles these challenges by proposing a scalable programming environment and architecture, aiming to substantially reduce energy consumption as well as data traffic and latency. ECOSCALE introduces a novel heterogeneous energy-efficient hierarchical architecture, as well as a hybrid many-core+OpenCL programming environment and runtime system. The ECOSCALE approach is hierarchical and is expected to scale well by partitioning the physical system into multiple independent Workers (i.e. compute nodes). Workers are interconnected in a tree-like fashion and define a contiguous global address space that can be viewed either as a set of partitions in a Partitioned Global Address Space (PGAS), or as a set of nodes hierarchically interconnected via an MPI protocol. To further increase energy efficiency, as well as to provide resilience, the Workers employ reconfigurable accelerators mapped into the virtual address space utilizing a dual stage System Memory Management Unit with coherent memory access. The architecture supports shared partitioned reconfigurable resources accessed by any Worker in a PGAS partition, as well as automated hardware synthesis of these resources from an OpenCL-based programming model.