A Survey of FPGA Optimization Methods for Data Center Energy Efficiency

This article provides a survey of academic literature about field programmable gate array (FPGA) and their utilization for energy efficiency acceleration in data centers. The goal is to critically present the existing FPGA energy optimization techniques and discuss how they can be applied to such systems. To do so, the article explores current energy trends and their projection to the future with particular attention to the requirements set out by the European Code of Conduct for Data Center Energy Efficiency. The article then proposes a complete analysis of over ten years of research in energy optimization techniques, classifying them by purpose, method of application, and impacts on the sources of consumption. Finally, we conclude with the challenges and possible innovations we expect for this sector.Comment: Accepted for publication in IEEE Transactions on Sustainable Computin

Automatic Creation of High-Bandwidth Memory Architectures from Domain-Specific Languages: The Case of Computational Fluid Dynamics

Numerical simulations can help solve complex problems. Most of these algorithms are massively parallel and thus good candidates for FPGA acceleration thanks to spatial parallelism. Modern FPGA devices can leverage high-bandwidth memory technologies, but when applications are memory-bound designers must craft advanced communication and memory architectures for efficient data movement and on-chip storage. This development process requires hardware design skills that are uncommon in domain-specific experts. In this paper, we propose an automated tool flow from a domain-specific language (DSL) for tensor expressions to generate massively-parallel accelerators on HBM-equipped FPGAs. Designers can use this flow to integrate and evaluate various compiler or hardware optimizations. We use computational fluid dynamics (CFD) as a paradigmatic example. Our flow starts from the high-level specification of tensor operations and combines an MLIR-based compiler with an in-house hardware generation flow to generate systems with parallel accelerators and a specialized memory architecture that moves data efficiently, aiming at fully exploiting the available CPU-FPGA bandwidth. We simulated applications with millions of elements, achieving up to 103 GFLOPS with one compute unit and custom precision when targeting a Xilinx Alveo U280. Our FPGA implementation is up to 25x more energy efficient than expert-crafted Intel CPU implementations

Automatic Generation of Heterogeneous SoC Architectures with Secure Communications

Heterogeneous Multiprocessor System-on-Chip (MPSoC) architectures allow designers to achieve energy efficiency and high performance, especially when tailored for the target applications. This specialization requires to select the MPSoC components and define their interconnections (on the architecture side), and also to determine the mapping and scheduling of tasks and communications (on the application side). This problem is exacerbated by the growing privacy and security concerns when these architectures elaborate sensitive data. We propose a co-design solution based on Ant Colony Optimization that also protects the exchange of private data among components. Our solution generates architectures with secure communications with systematically better performance than architectures with pre-defined security solutions

Setting up of an innovative procedure for redox proteomics and its application for definition of the redox status of a cellular model.

Human proteome contains 214.000 cysteine residues. In the subset of protein not-free thiols, these are alkylated or, most frequently, oxidized. While disulfides, the largely most abundant oxidized form, have a pivotal role in driving protein folding, recently, their reversible formation also came to the stage as the final outcome of cell signaling pathways under the control of the nucleophilic/electrophilic tone. Specific high throughput procedures, collectively known as redox proteomics, have been developed to pinpoint these functional redox transition. Here we present an approach for pairwise comparison, integrating differential labeling with cys reactive probes and chromatographic isolation of redox sensitive proteins

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 ± 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys

Effects of mode of delivery and infant feeding on the risk of mother-to-child transmission of hepatitis C virus

Objective To investigate the effects of mode of delivery and infant feeding on the risk of mother-to-child transmission of hepatitis C virus. Design Pooled retrospective analysis of prospectively collected data. Sample Data on hepatitis C virus seropositive mothers and their children identified around delivery were sent from 24 centres of the European Paediatric Hepatitis C Virus Network. Main outcome measures Hepatitis C virus infection status of children born to hepatitis C virus infected women. Results A total of 1,474 hepatitis C virus infected women were identified, of whom 503 (35%) were co-infected with HIV. Co-infected women were more than twice as likely to transmit hepatitis C virus to their children than women with hepatitis C virus infection alone. Overall 9.2% (136/1474) of children were hepatitis C virus infected. Among the women with hepatitis C virus infection-only, multivariate analyses did not show a significant effect of mode of delivery and breastfeeding: caesarean section vs vaginal delivery OR=1.17, P=0.66; breastfed versus non-breastfed OR=1.07, P=0.83. However, HIV co-infected women delivered by caesarean section were 60% less likely to have an infected child than those delivered vaginally (OR=0.36, P=0.01) and those who breastfed were about four times more likely to infect their children than those who did not (OR=6.41, P=0.03). HIV infected children were three to four times more likely also to be hepatitis C virus infected than children without HIV infection (crude OR=3.76, 95% CI 1.89\u20137.41). Conclusions These results do not support a recommendation of elective caesarean section or avoidance of breastfeeding for women with hepatitis C virus infection only, but the case for HIV infected women undergoing caesarean section delivery and avoiding breastfeeding is strengthened if they are also hepatitis C virus infected