Hierarchical clustered register file organization for VLIW processors

Technology projections indicate that wire delays will become one of the biggest constraints in future microprocessor designs. To avoid long wire delays and therefore long cycle times, processor cores must be partitioned into components so that most of the communication is done locally. In this paper, we propose a novel register file organization for VLIW cores that combines clustering with a hierarchical register file organization. Functional units are organized in clusters, each one with a local first level register file. The local register files are connected to a global second level register file, which provides access to memory. All intercluster communications are done through the second level register file. This paper also proposes MIRS-HC, a novel modulo scheduling technique that simultaneously performs instruction scheduling, cluster selection, inserts communication operations, performs register allocation and spill insertion for the proposed organization. The results show that although more cycles are required to execute applications, the execution time is reduced due to a shorter cycle time. In addition, the combination of clustering and hierarchy provides a larger design exploration space that trades-off performance and technology requirements.Peer ReviewedPostprint (published version

Stewardship of the evolving scholarly record: from the invisible hand to conscious coordination

The scholarly record is increasingly digital and networked, while at the same time expanding in both the volume and diversity of the material it contains. The long-term future of the scholarly record cannot be effectively secured with traditional stewardship models developed for print materials. This report describes the key features of future stewardship models adapted to the characteristics of a digital, networked scholarly record, and discusses some practical implications of implementing these models. Key highlights include: As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models. Past stewardship models were built on an "invisible hand" approach that relied on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections. Future stewardship of the evolving scholarly record requires conscious coordination of context, commitments, specialization, and reciprocity. With conscious coordination, local stewardship efforts leverage scale by collecting more of less. Keys to conscious coordination include right-scaling consolidation, cooperation, and community mix. Reducing transaction costs and building trust facilitate conscious coordination. Incentives to participate in cooperative stewardship activities should be linked to broader institutional priorities. The long-term future of the scholarly record in its fullest expression cannot be effectively secured with stewardship strategies designed for print materials. The features of the evolving scholarly record suggest that traditional stewardship strategies, built on an “invisible hand” approach that relies on the uncoordinated, institution-scale efforts of individual academic libraries acting autonomously to maintain local collections, is no longer suitable for collecting, organizing, making available, and preserving the outputs of scholarly inquiry. As the scholarly record continues to evolve, conscious coordination will become an important organizing principle for stewardship models. Conscious coordination calls for stewardship strategies that incorporate a broader awareness of the system-wide stewardship context; declarations of explicit commitments around portions of the local collection; formal divisions of labor within cooperative arrangements; and robust networks for reciprocal access. Stewardship strategies based on conscious coordination involve an acceleration of an already perceptible transition away from relatively autonomous local collections to ones built on networks of cooperation across many organizations, within and outside the traditional cultural heritage community

Virtual cluster scheduling through the scheduling graph

This paper presents an instruction scheduling and cluster assignment approach for clustered processors. The proposed technique makes use of a novel representation named the scheduling graph which describes all possible schedules. A powerful deduction process is applied to this graph, reducing at each step the set of possible schedules. In contrast to traditional list scheduling techniques, the proposed scheme tries to establish relations among instructions rather than assigning each instruction to a particular cycle. The main advantage is that wrong or poor schedules can be anticipated and discarded earlier. In addition, cluster assignment of instructions is performed using another novel concept called virtual clusters, which define sets of instructions that must execute in the same cluster. These clusters are managed during the deduction process to identify incompatibilities among instructions. The mapping of virtual to physical clusters is postponed until the scheduling of the instructions has finalized. The advantages this novel approach features include: (1) accurate scheduling information when assigning, and, (2) accurate information of the cluster assignment constraints imposed by scheduling decisions. We have implemented and evaluated the proposed scheme with superblocks extracted from Speclnt95 and MediaBench. The results show that this approach produces better schedules than the previous state-of-the-art. Speed-ups are up to 15%, with average speed-ups ranging from 2.5% (2-Clusters) to 9.5% (4-Clusters).Peer ReviewedPostprint (published version

Coarse-grained reconfigurable array architectures

Coarse-Grained Reconfigurable Array (CGRA) architectures accelerate the same inner loops that benefit from the high ILP support in VLIW architectures. By executing non-loop code on other cores, however, CGRAs can focus on such loops to execute them more efficiently. This chapter discusses the basic principles of CGRAs, and the wide range of design options available to a CGRA designer, covering a large number of existing CGRA designs. The impact of different options on flexibility, performance, and power-efficiency is discussed, as well as the need for compiler support. The ADRES CGRA design template is studied in more detail as a use case to illustrate the need for design space exploration, for compiler support and for the manual fine-tuning of source code

Farmers' rights and protection of traditional agricultural knowledge:

"Although achieving in situ conservation is possible without changing farmers' customary management of crops as common pool resources, an alternative approach is to negotiate a bioprospecting contract with providers of the resource that involves direct payment and royalties. This bioprospecting mechanism implies a change in the customary treatment of crop genetic resources as common pool goods and is in line with national ownership mandated by the Convention on Biological Diversity (CBD). This paper questions the value of bioprospecting for protecting traditional agricultural knowledge and argues for a common pool approach. It examines the nature of crop genetic resources and farmers' knowledge about them, and it analyzes the nature of the ‘common heritage' regime that was partly dismantled by the Convention on Biological Diversity. The paper reviews the implementation of access and benefit sharing schemes under the CBD and discusses programs to recognize Farmers' Rights that have arisen since the establishment of the CBD. It concludes with recommendations for meeting the Farmers' Rights mandate of the International Treaty on Plant Genetic Resources for Food and Agriculture." Author's AbstractEast Africa, africa south of sahara, Biological diversity conservation, Collective action, Bioprospecting,

Effect on smoking quit rate of telling patients their lung age: the Step2quit randomised controlled trial

Objective To evaluate the impact of telling patients their estimated spirometric lung age as an incentive to quit smoking.Design Randomised controlled trial.Setting Five general practices in Hertfordshire, England.Participants 561 current smokers aged over 35.Intervention All participants were offered spirometric assessment of lung function. Participants in intervention group received their results in terms of "lung age" (the age of the average healthy individual who would perform similar to them on spirometry). Those in the control group received a raw figure for forced expiratory volume at one second (FEV1). Both groups were advised to quit and offered referral to local NHS smoking cessation services.Main outcome measures The primary outcome measure was verified cessation of smoking by salivary cotinine testing 12 months after recruitment. Secondary outcomes were reported changes in daily consumption of cigarettes and identification of new diagnoses of chronic obstructive lung disease.Results Follow-up was 89%. Independently verified quit rates at 12 months in the intervention and control groups, respectively, were 13.6% and 6.4% (difference 7.2%, P=0.005, 95% confidence interval 2.2% to 12.1%; number needed to treat 14). People with worse spirometric lung age were no more likely to have quit than those with normal lung age in either group. Cost per successful quitter was estimated at 280 pound ((euro) 365, $556). A new diagnosis of obstructive lung disease was made in 17% in the intervention group and 14% in the control group; a total of 16% (89/561) of participants.Conclusion Telling smokers their lung age significantly improves the likelihood of them quitting smoking, but the mechanism by which this intervention achieves its effect is unclear.Trial registration National Research Register N0096173751