Erbium: A Deterministic, Concurrent Intermediate Representation for Portable and Scalable Performance

PosterInternational audienceOptimizing compilers and runtime libraries do not shield programmers from the complexity of multi-core hardware; as a result the need for manual, target-specific optimizations increases with every processor generation. High-level languages are being designed to express concurrency and locality without reference to a particular architecture. But compiling such abstractions into efficient code requires a portable, intermediate representation: this is essential for modular composition (separate compilation), for optimization frameworks independent of the source language, and for just-in-time compilation of bytecode languages. This paper introduces Erbium, an intermediate representation for compilers, a low-level language for efficiency programmers, and a lightweight runtime implementation. It relies on a data structure for scalable and deterministic concurrency, called Event Record, exposing the data-level, task and pipeline parallelism suitable to a given target. We provide experimental evidence of the productivity, scalability and efficiency advantages of Erbium, relying on a prototype implementation in GCC 4.3

Protective Action of Resveratrol in Human Skin: Possible Involvement of Specific Receptor Binding Sites

Background: Resveratrol is a plant-derived polyphenol with purported protecting action on various disorders associated with aging. It has been suggested that resveratrol could exert its protective action by acting on specific plasma membrane polyphenol binding sites (Han Y.S., et al. (2006) J Pharmacol Exp Ther 318:238–245). The purpose of this study was to investigate, in human skin, the possible existence of specific binding sites that mediate the protective action of resveratrol. Methods and Findings: Using human skin tissue, we report here the presence of specific [ 3 H]-resveratrol binding sites (KD = 180 nM) that are mainly located in the epidermis. Exposure of HaCaT cells to the nitric oxide free radical donor sodium nitroprusside (SNP; 0.3–3 mM) resulted in cell death which was reduced by resveratrol (EC50 = 14.7 mM), and to a much lesser extent by the resveratrol analogue piceatannol (EC 50 =95 mM) and epigallocatechin gallate (EC 50 =200 mM), a green-tea derived polyphenol. The protective action of resveratrol likely relates to its anti-apoptotic effect since at the same range of concentration it was able to reduce both the number of apoptotic cells as well as mitochondrial apoptotic events triggered by SNP. Conclusion: Taken together, these findings suggest that resveratrol, by acting on specific polyphenol binding sites i

Application Domain-Driven System Design for Pervasive Video Processing

International audiencePervasive video processing in future Ambient Intelligence environments sets new challenges in embedded system design. In particular, very high performance requirements have to be combined with the constraints of deeply embedded systems, frequently changing operating modes, and low-cost, high-volume production. By leveraging upon the key properties of the application domain, we devised a computation model, a hardware template, and a programming approach which provide a natural mapping from application requirements to a complete system solution. Our approach enables the direct exploitation of concurrency and regularity in achieving the combined challenge of adaptability, performance, and efficiency

Multi-Periodic Process Networks: Technical Report

This paper aims at modeling video stream applications with structured data and multiple clocks. Multi-Periodic Process Networks (MPPN) are real-time process networks with an adaptable degree of synchronous behavior and a hierarchical structure. MPPN help to describe stream-processing applications and deduce resource requirements such as parallel functional units, throughput and buffer sizes

Multi-Periodic Process Networks: Prototyping and Verifying Stream-Processing Systems

International audienceModeling video and graphic streams with different clocks is largely an open problem. This article proposes a new kind of process network for application modeling, called Hierarchical Process Network. With properties such as abstraction, composition, synchronization and sequencing, hierarchy helps to describe stream-processing applications and deduce parameters such as throughput and buffer sizes more precisely. Real-time is explicit, as well as adaptable degrees of synchronous behavior

The SANDRA project: cooperative architecture/compiler technology for embedded real-time streaming applications

The convergence of digital television, Internet access, gaming, and digital media capture and playback stresses the importance of high-quality and high-performance video and graphics processing. The SANDRA project, a collaboration between Philips Research and INRIA, develops a consistent and efficient system design approach for regular, real-time constrained stream processing. The project aims at providing a system template with its associated compiler chain and application development framework, enabling an early validation of both the functional and the non-functional requirements of the application at every system design stage

ACOTES project: Advanced compiler technologies for embedded streaming

Streaming applications are built of data-driven, computational components, consuming and producing unbounded data streams. Streaming oriented systems have become dominant in a wide range of domains, including embedded applications and DSPs. However, programming efficiently for streaming architectures is a challenging task, having to carefully partition the computation and map it to processes in a way that best matches the underlying streaming architecture, taking into account the distributed resources (memory, processing, real-time requirements) and communication overheads (processing and delay). These challenges have led to a number of suggested solutions, whose goal is to improve the programmer’s productivity in developing applications that process massive streams of data on programmable, parallel embedded architectures. StreamIt is one such example. Another more recent approach is that developed by the ACOTES project (Advanced Compiler Technologies for Embedded Streaming). The ACOTES approach for streaming applications consists of compiler-assisted mapping of streaming tasks to highly parallel systems in order to maximize cost-effectiveness, both in terms of energy and in terms of design effort. The analysis and transformation techniques automate large parts of the partitioning and mapping process, based on the properties of the application domain, on the quantitative information about the target systems, and on programmer directives. This paper presents the outcomes of the ACOTES project, a 3-year collaborative work of industrial (NXP, ST, IBM, Silicon Hive, NOKIA) and academic (UPC, INRIA, MINES ParisTech) partners, and advocates the use of Advanced Compiler Technologies that we developed to support Embedded Streaming.Peer ReviewedPostprint (published version

Acute Activation of AMP-Activated Protein Kinase Prevents H2O2-Induced Premature Senescence in Primary Human Keratinocytes

We investigated the effects of AMPK on H2O2-induced premature senescence in primary human keratinocytes. Incubation with 50 µM H2O2 for 2 h resulted in premature senescence with characteristic increases in senescence-associated ß-galactosidase (SA-gal) staining 3 days later and no changes in AMPK or p38 MAPK activity. The increase in SA-gal staining was preceded by increases in both p53 phosphorylation (S15) (1 h) and transactivation (6 h) and the abundance of the cyclin inhibitor p21CIP1 (16 h). Incubation with AICAR or resveratrol, both of which activated AMPK, prevented the H2O2-induced increases in both SA-Gal staining and p21 abundance. In addition, AICAR diminished the increase in p53 transactivation. The decreases in SA-Gal expression induced by resveratrol and AICAR were prevented by the pharmacological AMPK inhibitor Compound C, expression of a DN-AMPK or AMPK knock-down with shRNA. Likewise, both knockdown of AMPK and expression of DN-AMPK were sufficient to induce senescence, even in the absence of exogenous H2O2. As reported by others, we found that AMPK activation by itself increased p53 phosphorylation at S15 in embryonic fibroblasts (MEF), whereas under the same conditions it decreased p53 phosphorylation in the keratinocytes, human aortic endothelial cells, and human HT1080 fibrosarcoma cells. In conclusion, the results indicate that H2O2 at low concentrations causes premature senescence in human keratinocytes by activating p53-p21CIP1 signaling and that these effects can be prevented by acute AMPK activation and enhanced by AMPK downregulation. They also suggest that this action of AMPK may be cell or context-specific