A memory-centric approach to enable timing-predictability within embedded many-core accelerators

There is an increasing interest among real-time systems architects for multi- and many-core accelerated platforms. The main obstacle towards the adoption of such devices within industrial settings is related to the difficulties in tightly estimating the multiple interferences that may arise among the parallel components of the system. This in particular concerns concurrent accesses to shared memory and communication resources. Existing worst-case execution time analyses are extremely pessimistic, especially when adopted for systems composed of hundreds-tothousands of cores. This significantly limits the potential for the adoption of these platforms in real-time systems. In this paper, we study how the predictable execution model (PREM), a memory-aware approach to enable timing-predictability in realtime systems, can be successfully adopted on multi- and manycore heterogeneous platforms. Using a state-of-the-art multi-core platform as a testbed, we validate that it is possible to obtain an order-of-magnitude improvement in the WCET bounds of parallel applications, if data movements are adequately orchestrated in accordance with PREM. We identify which system parameters mostly affect the tremendous performance opportunities offered by this approach, both on average and in the worst case, moving the first step towards predictable many-core systems

Convolutional Neural Networks on Embedded Automotive Platforms: A Qualitative Comparison

In the last decade, the rise of power-efficient, het- erogeneous embedded platforms paved the way to the effective adoption of neural networks in several application domains. Especially, many-core accelerators (e.g., GPUs and FPGAs) are used to run Convolutional Neural Networks, e.g., in autonomous vehicles, and industry 4.0. At the same time, advanced research on neural networks is producing interesting results in computer vision applications, and NN packages for computer vision object detection and categorization such as YOLO, GoogleNet and AlexNet reached an unprecedented level of accuracy and perfor- mance. With this work, we aim at validating the effectiveness and efficiency of most recent networks on state-of-the-art embedded platforms, with commercial-off-the-shelf System-on-Chips such as the NVIDIA Tegra X2 and Xilinx Ultrascale+. In our vision, this work will support the choice of the most appropriate CNN package and computing system, and at the same time tries to “make some order” in the field

Piattaforme multicore e integrazione tri-dimensionale: analisi architetturale e ottimizzazione

Modern embedded systems embrace many-core shared-memory designs. Due to constrained power and area budgets, most of them feature software-managed scratchpad memories instead of data caches to increase the data locality. It is therefore programmers’ responsibility to explicitly manage the memory transfers, and this make programming these platform cumbersome. Moreover, complex modern applications must be adequately parallelized before they can the parallel potential of the platform into actual performance. To support this, programming languages were proposed, which work at a high level of abstraction, and rely on a runtime whose cost hinders performance, especially in embedded systems, where resources and power budget are constrained. This dissertation explores the applicability of the shared-memory paradigm on modern many-core systems, focusing on the ease-of-programming. It focuses on OpenMP, the de-facto standard for shared memory programming. In a first part, the cost of algorithms for synchronization and data partitioning are analyzed, and they are adapted to modern embedded many-cores. Then, the original design of an OpenMP runtime library is presented, which supports complex forms of parallelism such as multi-level and irregular parallelism. In the second part of the thesis, the focus is on heterogeneous systems, where hardware accelerators are coupled to (many-)cores to implement key functional kernels with orders-of-magnitude of speedup and energy efficiency compared to the “pure software” version. However, three main issues rise, namely i) platform design complexity, ii) architectural scalability and iii) programmability. To tackle them, a template for a generic hardware processing unit (HWPU) is proposed, which share the memory banks with cores, and the template for a scalable architecture is shown, which integrates them through the shared-memory system. Then, a full software stack and toolchain are developed to support platform design and to let programmers exploiting the accelerators of the platform. The OpenMP frontend is extended to interact with it.I sistemi integrati moderni sono architetture many-core, in cui spesso lo spazio di memoria è condiviso fra i processori. Per ridurre i consumi, molte di queste architetture sostituiscono le cache dati con memorie scratchpad gestite in software, per massimizzarne la località alle CPU e aumentare le performance. Questo significa che i dati devono essere spostati manualmente da parte del programmatore. Inoltre, tradurre in perfomance l’enorme parallelismo potenziale delle piattaforme many-core non è semplice. Per supportare la programmazione, diversi programming model sono stati proposti, e siccome lavorano ad un alto livello di astrazione, sfruttano delle librerie di runtime che forniscono servizi di base quali sincronizzazione, allocazione della memoria, threading. Queste librerie hanno un costo, che nei sistemi integrati è troppo elevato e ostacola il raggiungimento delle piene performance. Questa tesi analizza come un programming model ad alto livello di astrazione – OpenMP – possa essere efficientemente supportato, se il suo stack software viene adattato per sfruttare al meglio la piattaforma sottostante. In una prima parte, studio diversi meccanismi di sincronizzazione e comunicazione fra thread paralleli, portati sulle piattaforme many-core. In seguito, li utilizzo per scrivere un runtime di supporto a OpenMP che sia il più possibile efficente e “leggero” e che supporti paradigmi di parallelismo multi-livello e irregolare, spesso presenti nelle applicazioni moderne. Una seconda parte della tesi esplora le architetture eterogenee, ossia con acceleratori hardware. Queste architetture soffrono di problematiche sia i) per il processo di design della piattaforma, che ii) di scalabilità della piattaforma stessa (aumento del numero degli acceleratori e dei processori), che iii) di programmabilità. La tesi propone delle soluzioni a tutti e tre i problemi. Il linguaggio di programmazione usato è OpenMP, sia per la sua grande espressività a livello semantico, sia perché è lo standard de-facto per programmare sistemi a memoria condivisa

Different distribution patterns of hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) along altitudinal gradients in Dolomiti Bellunesi National Park (Italy)

Hoverflies (Diptera: Syrphidae) and bees (Hymenoptera: Anthophila) are two key taxa for plant pollination. In the present research, the altitudinal distribution of these taxa was studied along two gradients (elevation range: 780–2130 m) in the Dolomiti Bellunesi National Park (Northeastern Italy). Pan traps were used as a sampling device to collect both hoverflies and bees. Other than altitude, the effect of landscape complexity and plant diversity were considered as potential predictors of hoverfly and bee richness and abundance along the two gradients. A total of 68 species of hoverflies and 67 of bees were collected during one sampling year, confirming the efficacy of pan traps as a sampling device to study these taxa. Altitude was the main variable affecting both hoverfly and bee distribution. The two taxa show different distribution patterns: hoverflies have a unimodal distribution (richness and abundance) with peak at middle altitude (1500 m), while bees have a monotonic decline (richness and abundance) with increasing altitude. Both hoverfly and bee populations change with the increasing altitude, but the change in hoverflies is more pronounced than in bees. Species turnover dominates the β-diversity both for hoverflies and bees; therefore, the hoverfly and bee communities at higher altitudes are not subsamples of species at lower altitude but are characterized by different species. This poses important conservation consequences. Some rare species, typical of an alpine habitat were recorded; the present research represents important baseline data to plan a monitoring scheme aimed at evaluating the effect of climate change on pollinators in these fragile habitat

The Key Role of Memory in Next-Generation Embedded Systems for Military Applications

With the increasing use of multi-core platforms in safety-related domains, aircraft system integrators and authorities exhibit a concern about the impact of concurrent access to shared-resources in the Worst-Case Execution Time (WCET). This paper highlights the need for accurate memory-centric scheduling mechanisms for guaranteeing prioritized memory accesses to Real-Time safety-related components of the system. We implemented a software technique called cache coloring that demonstrates that isolation at timing and spatial level can be achieved by managing the lines that can be evicted in the cache. In order to show the effectiveness of this technique, the timing properties of a real application are considered as a use case, this application is made of parallel tasks that show different trade-offs between computation and memory loads

Gluon condensation and deconfinement critical density in nuclear matter

An upper limit to the critical density for the transition to the deconfined phase, at zero temperature, has been evaluated by analyzing the behavior of the gluon condensate in nuclear matter. Due to the non linear baryon density effects, the upper limit to the critical density, \rho_c turns out about nine times the saturation density, rho_0 for the value of the gluon condensate in vacuum =0.012 GeV^4. For neutron matter \rho_c \simeq 8.5 \rho_0. The dependence of the critical density on the value of the gluon condensate in vacuum is studied.Comment: Published version, 11 pages, 2 eps figure

High-performance parallelisation of real-time applications

Paper presented at the Embedded World Conference 2017. 14 to 16, Mar, 2017, Session 19: HiPEAC – High Performance Embedded Architectures. Nuremberg, Germany.This paper presents an overview of the P-SOCRATES methodology and tools, instantiated in the UpScale SDK (Software Development Kit) for the development of time-predictable high-performance applications. The proposed methodology was designed to provide an integrated SDK to fully exploit the huge performance opportunities brought by the most advanced many-core processors, whilst ensuring a predictable performance and maintaining (or even reducing) development costs of applications. The paper also provides the performance results of the application of the SDK in relevant embedded usecases.info:eu-repo/semantics/publishedVersio

Reactive oxygen intermediates mediate angiotensin II-induced c-Jun.c-Fos heterodimer DNA binding activity and proliferative hypertrophic responses in myogenic cells

Angiotensin II (Ang-II) receptor engagement activates many immediate early response genes in both vascular smooth muscle cells and cardiomyocytes whether a hyperplastic or hypertrophic response is taking place. Although the signaling pathways stimulated by Ang-II in different cell lines have been widely characterized, the correlation between the generation of different second messengers and specific physiological responses remains relatively unexplored. In this study, we report how in both C2C12 quiescent myoblasts and differentiated myotubes Ang-II significantly stimulates AP1-driven transcription and c-Jun.c-Fos heterodimer DNA binding activity. Using a set of different protein kinase inhibitors, we could demonstrate that Ang-II-induced increase in AP1 binding is not mediated by the cAMP-dependent pathway and that both protein kinase C and tyrosine kinases are involved. The observation that in quiescent myoblasts Ang-II increase of AP1 binding and induction of DNA synthesis and, in differentiated myotubes, Ang-II stimulation of protein synthesis are abolished by the cysteine-derivative and glutathione precursor N-acetyl-L-cysteine strongly suggests a role for reactive oxygen intermediates in the intracellular transduction of Ang-II signals for immediate early gene induction, cell proliferation, and hypertrophic responses

F1/10: An Open-Source Autonomous Cyber-Physical Platform

In 2005 DARPA labeled the realization of viable autonomous vehicles (AVs) a grand challenge; a short time later the idea became a moonshot that could change the automotive industry. Today, the question of safety stands between reality and solved. Given the right platform the CPS community is poised to offer unique insights. However, testing the limits of safety and performance on real vehicles is costly and hazardous. The use of such vehicles is also outside the reach of most researchers and students. In this paper, we present F1/10: an open-source, affordable, and high-performance 1/10 scale autonomous vehicle testbed. The F1/10 testbed carries a full suite of sensors, perception, planning, control, and networking software stacks that are similar to full scale solutions. We demonstrate key examples of the research enabled by the F1/10 testbed, and how the platform can be used to augment research and education in autonomous systems, making autonomy more accessible

Isolation of biofilm producing microorganisms isolated from urinary indwelling catheter in geriatric hospitalized patients

Introduction: In nature, bacterial cells can exist in two different states: individual (planktonic) cells, or biofilm. In biofilms, bacterial cells are adherent to a surface and contained in an extracellular matrix mainly composed of polysaccharides and proteins.The cells in biofilms differ from planktonic counterparts for a different pattern of gene expression and increased resistance to antibiotics.This means that biofilms in hospital can cause persistent infections, due to the immunocompromised state of the patient and from a previous infection or exposure to the antibiotic. The aim of our work was to: 1) to assess the presence of microorganisms in institutionalized geriatric patients carrying indwelling catheter 2) assess the ability of gram-negative microorganisms to produce biofilm. Methods: 150 samples from urine of patients with indwelling urinary catheter hospitalized at ASP Pio Albergo Trivulzio were studied. Adhesion of bacteria was tested using LB medium diluted 1:4 and staining the biofilm cells with crystal violet. Results: 120 samples (80%) tested positive for the presence of microorganisms; in 96 samples only one microrganism was detected, while 24 were contaminated with 2 or more bacterial species. 88% of isolates testing positive to a single species consisted of Gram negative microorganisms: E. coli (48%), P. mirabilis (16%), P. aeruginosa (13%), K. pneumoniae (5%), P. stuartii (2%), C. freundii (1%), E. aerogenes (1%), E. cloacae (1%), K. oxytica (1%), M. morganii (1%).Adhesion assays show that all strains of P. aeruginosa, K. pneumoniae, K. oxytoca, E. cloacae and C. freundii isolates produced biofilm. In contrast, strains of E. aerogenes and M. morganii did not produce any biofilm. 26% of E. coli strains were able to produce biofilm, as well as 93% of P. mirabilis and 50% of P. stuartii.Overall, 55% of Gram negative microrganisms isolated were capable of producing biofilms. Conclusion: The use of a nutritionally poor medium (LB diluted 1:4) and a synthetic substrate define an experimental model in vitro that plays in a relatively faithful to what may occur in vivo. The fact that biofilms are known to be more tolerant to antibiotics and the high proportion of biofilm-forming bacteria isolated from patients carrying indwelling underlines the need for novel antimicrobial agents with higher potency on bacterial biofilms than the ones currently used in therapy