6607773
DMDC: Delayed Memory Dependence Checking through Age-Based Filtering
One of the main challenges of modern processor design is the implementation of a scalable and efficient mechanism to detect memory access order violations as a result of out-of-order execution of memory instructions. Traditional CAM-based associative queues can be very slow and energy hungry. In this paper we introduce two new management schemes. The first one is a filtering scheme based on simple age-tracking. This scheme can easily avoid 95-98% of associative load queue (LQ) searches using only a few registers. This translates into significant power savings. More importantly, however, this filtering makes our second scheme, delayed memory dependence checking (DMDC), practical. With a small hash table, DMDC completely avoids the need for an associative LQ and relies on indexing-based checking at the commit phase and hence cuts the energy spent on LQ by an average of 95%. At an average of about 0.3%, the performance impact is negligible. When the energy cost of the increased execution time is factored in, the processor still makes net energy savings of about 3-8%, depending on the configuration and the applications
7442937
SEED: Scalable, efficient enforcement of dependences
Instruction issue logic is a critical component in modern high-performance out-of-order processors. The ever increasing latencies found in modern processors, mostly associated with memory accesses and longer pipelines, can be attenuated using large issue queues. Conventional designs rely on atomic wakeup-select cycles to ensure compact scheduling. These designs must aggressively utilize broadcasting, compaction, and heavily-ported structures that scale poorly in terms of both power consumption and access time. To provide high scheduling flexibility and large instruction capacity without incurring prohibitive latency and energy overhead, we propose a novel scheme that uses an out-of-order, broadcast-free instruction wakeup block feeding an in-order scheduler. Multi-banked, index-based structures are used throughout this scheme to provide a high degree of scalability while achieving efficient dependence tracking, resulting in good overall performance and energy efficiency. We call this design "Scalable, Efficient Enforcement of Dependences (SEED)". We present a detailed design and analysis of SEED through an extensive evaluation. Compared to a conventional issue queue design, which is assumed favorably to scale in size without any impact on cycle time, the performance degradation of our design is 3% for both INT and FP suites of SPEC CPU2000. For such a small performance cost, SEED enjoys a 19% reduction in total chip power consumption for a 32-entry configuration. We also synthesize SEED and a conventional issue logic with 90nm standard cell logic. Synthesis results show that SEED can cycle twice the speed of a conventional issue logic of equivalent size. Cycling at the same frequency, SEED consumes ten times less dynamic power and five times less static power while achieving substantial area savings.
847742
Information Visualization of Attributed Relational Data
Traditional graph drawing is only concerned with viewing of abstract data and relations amount data items. It uses a graph model to present the data items and the relations and tries to geometrically convert the abstract graph into a 2D plane for visualization. There are many applications in this area, such as family trees, software design diagrams and web site-maps.The real world data that we want to visualize, however, is more complex than those that can be simply presented with traditional techniques, because it contains many domain-specific attributes.For example, in a web site-map (visualization) a simple graphical node can be used to represent a web page. However, this node is unable to represent some domain-specific attributes associated with the web page, such as the access frequency and the connectivity of the page in the web locality.This paper introduces a new model for Attributed Information Visualization that can be used to visualize the relational data with many associated attributes. We split the visualization model into two mappings between the abstract data and physical pictures, Geometric Mapping and Graphical Mapping.
4678514
Steering Model-Driven Development of Enterprise Information System Through Responsibilities
OMG proposes the MDA that promotes the ideas of modeling in UML and transforming UML models to code. But UML is not universal for every domain and the direct translation approach of the MDA is not adequate. In this paper, we introduce REST, an idea of using responsibilities as contextual information to instruct machines to generate software systems. First, we give an overview of RESTDA a software development architecture for business based on the concept of REST. Then we describe a domain-specific language Business Models. It helps developers to describe a business from a documentprocessing perspective. We also introduce a rule-based validation of consistency within Business Models. Finally, we describe the transformation mechanism of RESTDA. Our approach provides machines higher intelligence to generate source code for different contexts.
3067574
Steering model-driven evolution by responsibilities
The model-driven development approach provides an alternative solution to human-centered software evolution. In this paper, we propose using the concept of responsibility to define model mapping where responsibility represents a high-level description of "tasks to be accomplished by something". Based on this concept, we have created RESTDA, a development architecture for building enterprise information systems. In RESTDA, a software system is defined by three world levels and two views. The three world levels represent different levels of abstraction within the software system. The two views separate the structural concepts and behavioral concepts of each world level. RESTDA applies a two-phase generation. The first phase generates an intermediate model from high-level models. The second phase generates code from the intermediate model. The automatic transformation promises that any change to the business requirements results in corresponding code generation. The intermediate model separates changes to the underlying implementation technology from the top-most level.
31352363
Some Computational Problems of Cryptographic Significance Concerning Elliptic Curves over Rings
Elliptic curves over the ring Zn were first employed by Lenstra [Len1, Len2] to present his algorithm on factorization of integers. These curves have also been used to construct new public-key cryptographic schemes [Dem, Koy, KMOV, Men]. Elliptic analogs of the RSA-scheme have been proposed in [Dem, Koy, KMOV], and an elliptic analog of Rabin-type scheme has been proposed in [KMOV]. In this paper we consider the following computational problems of cryptographic significance concerning elliptic curves over the ring Zn with n being square-free: (1) Given an odd positive integer n, and integers a, b such that 4a+27b is prime to n, to compute the number of rational points on the elliptic curve E defined by Y=X +aX+b over Zn . (2) Given an odd positive integer n, integers a, b with 4a+27b prime to n, and a point P=(u, v) on the elliptic curve E defined by Y=X+aX+b over Zn , where u, v # Zn , to find a rational point Q on E such that 2Q=P.
62155376
In VINI veritas: realistic and controlled network experimentation
This paper describes VINI, a virtual network infrastructure that allows network researchers to evaluate their protocols and services in a realistic environment that also provides a high degree of control over network conditions. VINI allows researchers to deploy and evaluate their ideas with real routing software, traffic loads, and network events. To provide researchers flexibility in designing their experiments, VINI supports simultaneous experiments with arbitrary network topologies on a shared physical infrastructure. This paper tackles the following important design question: What set of concepts and techniques facilitate flexible, realistic, and controlled experimentation (e.g., multiple topologies and the ability to tweak routing algorithms) on a fixed physical infrastructure? We first present VINI's high-level design and the challenges of virtualizing a single network. We then present PL-VINI, an implementation of VINI on PlanetLab, running the "Internet In a Slice". Our evaluation of PL-VINI shows that it provides a realistic and controlled environment for evaluating new protocols and services.