XeMPUPiL. Towards a performance aware power capping orchestrator for the Xen hypervisor

LAUREA MAGISTRALEAl giorno d’oggi stiamo assistendo all’affermazione di un nuovo paradigma computazionale: il cloud computing. In questa nuova era, detta epoca dell’aaS, le applicazione e i servizi non vengono più eseguiti su macchine di proprietà, ma bensì su macchine (spesso virtuali) di fornite da terzi: i così detti cloud provider. Dal punto di vista degli utenti questo permette loro di accedere a queste risorse computazionali in maniera elastica e scalabile, permettendo di dimensionare facilmente le loro necessità computazionali a seconda delle variazioni del mercato o anche solo all’interno della giornata lavorativa, riducendo in questa maniera i costi e i danni economici in caso di errore nella stima delle risorse ri- chieste. D’altra parte questo "nuovo mondo" ha spostato tutti quelli che erano i costi di gestione delle macchine fisiche sulle spalle dei cloud provider. Inoltre l’attrattiva che questo nuovo paradigma porta con se, ha spinto sempre più clienti ad adottare approcci basati sul cloud computing. L’incremento di utenti affacciatesi a questo paradigma ha portato al sorgere di due sfide per i gestori del cloud, in particolare due sfide riguardanti la gestione dei datacenter. In modo da rispondere alla crescente domanda i gestori di datacenter devono aumentare la loro potenza computazionale e per farlo sono costretti ad aumentare il numero di server presenti nelle loro strutture rischiando quindi di saturare e sforare lo spazio fisico della struttura oppure di non rispettare i contratti con i fornitori energetici, incappando in penali o blackout. Per risolvere questi problemi diverse tecniche di ottimizzazioni delle risorse all’interno di un datacenter e di gestione dei carichi di lavoro sono stati promossi. Su tutti spiccano le tecniche di virtualizzazione, ormai diventate una prassi adottata da tutti i cloud provider. In questo modo è possibile sfruttare una macchina fisica da più utenti, aumentandone così l’efficienza. In questo scenario, il consumo di potenza rimane uno dei costi principali di ogni sistema digitale. Diversi approcci hanno provato, in letteratura, ad affrontare il problema dei consumi e limiti di potenza, provando a massimizzare le prestazioni delle applicazioni ospitate. Questi approcci sono comunemente classificati in due macro famiglie, quella software e quella hardware. La prima è tipicamente adottata quando l’obiettivo consiste in minimizzare il consumo di potenza e allo stesso tempo fornendo le performance migliori per i carichi di lavoro del sistema. Questa famiglia è caratterizzata dall’ottenimento di alta efficienza, ma dalla mancanza di tempestività. Al contrario, la seconda famiglia è usata quando ci sono vincoli stringenti riguardanti il budget di potenza e l’obiettivo principale consiste nel rispettarlo e contemporaneamente provare a massimizzare le performance delle applicazioni in esecuzione. In questo caso, la caratteristica principale consiste nel rispettare il concetto di tempestività, trascurando completamente il concetto di efficienza. In questa tesi presentiamo una metodologia così detta ibrida, che cerca di sfruttare contemporaneamente sia un approccio software (un ciclo di controllo ODA) e un approccio hardware (Intel RAPL) in modo da nascondere i punti deboli dei due approcci quando presi singolarmente, ottenendo in questo modo sia efficienza the tempestività. Lo sviluppo di questa metodologia sfocia nel design di un orchestratore performance-aware e in grado di effettuare power capping sviluppato per l’hypervisor Xen, come prova di concetto. La soluzione proposta, chiamata XeMPUPiL, sfrutta la tecnologia RAPL di Intel tramite le sue interfacce hardware per definire un limite stringente sui consumi di potenza del processore, mentre a livello software un ciclo di controllo basato su strategia ODA si occupa di un’esplorazione delle possibili configurazioni riguardanti l’allocazione delle risorse ai vari carichi di lavoro, in modo da trovare quella corrispondente alla più power efficient. Per sfruttare al tecnologia RAPL siamo andati a sviluppare un tool stack che lavora a tutti e 3 i livelli della canonica pila di un ambienta virtualizzato, cioè: livello hardware, livello hypervisor e livello Virtual Machines (VMs). Per far questo abbiamo usato una serie di meccanismi propri delle tecnologie di virtualizzazione in modo da ottenere privilegi sull’hardware, le così dette hypecall (simili per comportamento alle syscall in un Operating System (OS) comune). Questo tools stack è poi stato sfruttato nella fase di Attuazione del ciclo di controllo ODA in modo da definire e far rispettare il power cap. Sempre in questo stadio andiamo inoltre ad attuare la configurazione delle risorse decisa per questa iterazione del ciclo di controllo, ripartendo le risorse virtuali delle VMs su quelle fisiche. Nella fase di Osservazione invece siamo andati a sviluppare un sistema di monitoring agnostico che valuta come stanno performando le VM eseguite nel sistema tramite metriche hardware quali il numero di IR, recuperate dai Model Specific Registers (MSRs). Infine, nella fase Decisionale andiamo ad esplorare, tramite ricerca binaria in intervallo chiuso, la prossima configurazione delle risorse da esplorare in modo da massimizzare le risorse. In questa tesi mostreremo XeMPUPiL è in grado di raggiungere performance migliori sotto differenti power cap per diverse tipologie di carico analizzate (e.g., CPU-, memory- and IO-bound). Inoltre mostriamo anche come è possibile sfruttare la stessa metodologia per ribaltare il problema e quindi dato un SLA da rispettare cercare di minimizzare i consumi di potenza del sistema.In the era of Cloud Computing, applications and computational power are provided in an as a Service (aaS) fashion, reducing the need of buying, build- ing and maintaining proprietary systems. In the last few years, many services moved from being proprietary and built in loco, to the as a Service paradigm. This was possible thanks to virtualization techniques, which allowed multiple applications to easily run on the same machine. However, the burden of costs optimization is left to the Cloud Provider, that still faces the problem of consolidating multiple workloads on the same infrastructure. As power consumption remains one of the most impacting costs of any digital system, several approaches have been explored in literature to cope with power caps, trying to maximize the performance of the hosted applications. These approaches were usually classified in two macro families, the software and hardware techniques. The former family is typically adopted when the goal consists in minimizing the power consumption, while providing the best possible performance for the running workloads. These approaches are characterized by obtaining high efficiency, but lacks in timeliness. Instead, the latter family is exploited when there are strict constraints regarding the power budget and the main goal consists in respecting them, while trying to maximize the performance of the running applications. In this case, the main characteristic consists in respecting the concept of timeliness, totally neglecting the concept of efficiency. In this thesis, we present results and opportunities obtained towards a performance-aware power capping orchestrator for the Xen hypervisor, that exploit a novel emerging family introduced in the literature: the hybrid approach. This fresh set of techniques aims to adopt synergically and concurrently both hardware and software approaches in order to achieve at the same time the concept of efficiency and timeliness, mask- ing the weak spots of the two common approaches when adopted alone. The proposed solution, called XeMPUPiL, uses the Intel RAPL hardware interface to set a strict limit on the processor’s power consumption, while a software-level ODA control loop performs an exploration of the available resource allocations to find the most power efficient one for the running workload. We show how the XeMPUPiL methodology is able to allow the definition of two different policies: achieving higher performance under different power caps and minimizing power consumption while respecting a given SLA for almost all the different classes of benchmarks analyzed (e.g., CPU-, memory- and IO-bound)

The VMC survey - XI : Radial Stellar Population Gradients in the Galactic Globular Cluster 47 Tucanae

Copyright American Astronomical SocietyWe present a deep near-infrared color-magnitude diagram of the Galactic globular cluster 47 Tucanae, obtained with the Visible and Infrared Survey Telescope for Astronomy (VISTA) as part of the VISTA near-infrared Y, J, Ks survey of the Magellanic System (VMC). The cluster stars comprising both the subgiant and red giant branches exhibit apparent, continuous variations in color-magnitude space as a function of radius. Subgiant branch stars at larger radii are systematically brighter than their counterparts closer to the cluster core; similarly, red-giant-branch stars in the cluster's periphery are bluer than their more centrally located cousins. The observations can very well be described by adopting an age spread of ~0.5 Gyr as well as radial gradients in both the cluster's helium abundance (Y) and metallicity (Z), which change gradually from (Y = 0.28, Z = 0.005) in the cluster core to (Y = 0.25, Z = 0.003) in its periphery. We conclude that the cluster's inner regions host a significant fraction of second-generation stars, which decreases with increasing radius; the stellar population in the 47 Tuc periphery is well approximated by a simple stellar population.Peer reviewe

GrOUT: Transparent Scale-Out to Overcome UVM's Oversubscription Slowdowns

Hardware accelerators have always been difficult to approach. In recent years, we have experienced great efforts to simplify their programming paradigms, especially on GPUs. This led to the development of various domain-specific frameworks and microarchitectural features that facilitated some aspects of this multifaced problem. One such feature is the Unified Virtual Memory (UVM) oversubscription mechanism that allows the developer to handle datasets with a bigger memory footprint than the HW accelerators. Although promising, current UVM faces extreme overheads when running large workloads that reach an oversubscription factor (allocated vs. available memory) ampler than a per-workload threshold. In this work, we propose GrOUT, a language- and domain-agnostic framework that tackles the slowdowns brought by the UVM oversubscription mechanism. In particular, we highlight how a scale-out approach is a feasible solution to solve the slowdowns brought by UVM on workloads from various domains. Moreover, we design a framework capable of autonomously scaling out user-provided workloads, reaching a speedup of more than 24.42 × with minimal changes to the application logic

Expression of Toll-like receptors 4 and 7 in the embryonic and adult pancreas, liver and adrenal gland of the mouse

The role of Toll protein in development and immunity is very well understood in Drosophila melanogaster (Anderson et al.,1985). Conversely, the contribution of Tolllike receptors (TLRs) in mammalian development is just beginning to be revealed. In this study, we evaluated the expression of TLR4 and TLR7 by immunohistochemistry on paraffin-embedded tissue in the adrenal gland, liver and pancreas of mouse embryos from stages E12, E14 and E16 and in the adult organs. Results show that TLR4 and TLR7 start to be detectable during embryonic development already at the first stage examined (E12). This expression follows the maturation of the organs and is still present in the adult with a different distribution pattern. Before this study no data in the literature were present on TLR4 and 7 expression in mammalian splanchnic organs development and in the adult no localization studies were available for TLR7. A possible interpretation of the results suggests that, besides their immunitary function, TLRs might be involved in a shared mechanism that regulates proliferation and differentiation both in embryonic organs and adult organs (Sato et al., 2009). These results also suggest that the contribution of TLRs in the context of carcinogenesis should be investigated not only in relation to chronic inflammation and tissue damage but also in relation to their contribution to the process of organogenesis

Expression of TLR7 in the murine eye during the embryonic period and in the adult animal

In the present study, we evaluated Toll-like receptor 7 (TLR7) expression at different stages of the murine eye development and in the adult organ. In mammals, TLRs are best known for their immunitary function, however data from the literature are demonstrating that in analogy to their Drosophila homologue Toll, they also participate in developmental mechanisms (Okun, Griffioen and Mattson 2011, Shechter et al. 2008). Immunohistochemistry for TLR7 and double immunofluorescence for TLR7/PCNA were performed on E12, E14 and E16 formalin-fixed paraffin-embedded mouse heads and on eyes enucleated from 3 months adult mice Results of experiments indicate that TLR7 expression is present in different compartments of the mouse eye (cornea, pigmented epithelium, neural retina, and lens) during gestation both in proliferating and differentiating cells and that such expression persists also in the adult organ. These observations indicate that besides being involved in protective mechanisms in the adult eye, TLR7 is also likely involved in the morphogenetic processes of this complex organ to which cells and tissues of different embryological origin contribute

Equivalence assessment of creams with quali-quantitative differences in light of the EMA and FDA regulatory framework

EMA and FDA are upgrading guidelines on assessing the quality and the equivalence of topically applied drug products for developing copies of originator products and supporting post-marketing variations. For topical products having remarkably similar composition, both EMA and FDA accept the equivalence on the bases of the comparison of rheological properties and in vitro drug release constant (k) and skin permeation flux (J) values, instead of clinical studies. This work aims to evaluate the feasibility to expand this approach to variations of the composition of complex semi-solid preparations. Ibuprofen (IB) creams at two different strengths (i.e., 1 % and 10 %) were used as a model formulation. Two formulative changes were performed: (a) the addition of the humectant to simulate a minor post-marketing variation; (b) the substitution of the emulsifying system to simulate a major one. These variations impacted only in 1 % IB formulations where both the equivalences of rheological data and J-values failed. At the highest concentration, the presence of IB crystals broke down the differences in rheological patterns and lead the IB thermodynamic activity at the maximum figuring out an overlapping of the J-values. Such data suggest the combination of these studies, which are thought mainly for the development of copies, could be also applied to the management of post-marketing variations that involve product composition

The Large ARtery Intracranial Occlusion Stroke Scale: A New Tool With High Accuracy in Predicting Large Vessel Occlusion

Objectives: The combination of systemic thrombolysis and mechanical thrombectomy is indicated in patients with ischemic stroke due to a large vessel occlusion (LVO) and these treatments are time-dependent. Rapid identification of patients with suspected LVO also in a prehospital setting could influence the choice of the destination hospital. Aim of this pilot study was to evaluate the predictive role of a new stroke scale for LVO, comparing it to other scores.Patients and Methods: All consecutive patients admitted to our comprehensive stroke center with suspected ischemic stroke were studied with a CT angiography and 5 different stroke scales were applied. The Large ARtery Occlusion (LARIO) stroke scale consists of 5 items including the assessment of facial palsy, language alteration, grip and arm weakness, and the presence of neglect. A Receiving Operating Characteristic curve was evaluated for each stroke scale to explore the level of accuracy in LVO prediction.Results: A total of 145 patients were included in the analysis. LVO was detected in 37.2% of patients. The Area Under Curve of the LARIO score was 0.951 (95%CI: 0.902–0.980), similar to NIHSS and higher than other scales. The cut-off score for best performance of the LARIO stroke scale was higher than 3 (positive predictive value: 77% and negative predictive value: 100%).Conclusion: The LARIO stroke scale is a simple tool, showing high accuracy in detecting LVO, even if with some limitations due to some false positive cases. Its efficacy has to be confirmed in a pre-hospital setting and other centers

ANTONIO: Towards a Systematic Method of Generating NLP Benchmarks for Verification

Verification of machine learning models used in Natural Language Processing (NLP) is known to be a hard problem. In particular, many known neural network verification methods that work for computer vision and other numeric datasets do not work for NLP. Here, we study technical reasons that underlie this problem. Based on this analysis, we propose practical methods and heuristics for preparing NLP datasets and models in a way that renders them amenable to known verification methods based on abstract interpretation. We implement these methods as a Python library called ANTONIO that links to the neural network verifiers ERAN and Marabou. We perform evaluation of the tool using an NLP dataset R-U-A-Robot suggested as a benchmark for verifying legally critical NLP applications. We hope that, thanks to its general applicability, this work will open novel possibilities for including NLP verification problems into neural network verification competitions, and will popularise NLP problems within this community.Comment: To appear in proceedings of 6th Workshop on Formal Methods for ML-Enabled Autonomous Systems (Affiliated with CAV 2023

Immunostaining patterns reveal potential morphogenetic role of Toll-like receptors 4 and 7 in the development of mouse respiratory system, liver and pancreas

Toll-like receptors (TLRs) are the mammalian ortholog of Drosophila melanogaster protein Toll, originally identified for its involvement in embryonic development. In mammals, TLRs are mainly known for their ability to recognize pathogen- or damage-associated molecular patterns and, consequently, to initiate the immune response. However, it is becoming clear that TLRs can play a role also in mammal embryo development. We have previously described TLR4 and TLR7 expression in developing mouse peripheral nervous system and gastrointestinal tract. In the present study, we extended the investigation of TLR4 and TLR7 to the respiratory system and to the two main accessory organs of the digestive system, the liver and pancreas. TLR4 and TLR7 immunostaining was performed on mouse conceptuses collected at different stages, from E12 to E18. TLR4 and TLR7 immunoreactivity was evident in the embryo pancreas and liver at E12, while, in the respiratory apparatus, appeared at E14 and E17, respectively. Although further studies are required to elucidate the specific role of these TLRs in embryo development, the differential spatiotemporal TLR4 and TLR7 appearance may suggest that TLR expression in developing embryos is highly regulated for a possible their direct involvement in the formation of the organs and in the acquisition of immune-related features in preparation for the birth