Ada 95 adds many new, powerful constructs to the ones Ada 83 already offered. From the perspective of a designer and implementor of Ada software components, this should encourage an evolution in the architecture of co...
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MAP has been developed to address the need for an analysis and design method which directly supports software development using a functional language. MAP breaks down software development into a set of manageable and ...
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MAP has been developed to address the need for an analysis and design method which directly supports software development using a functional language. MAP breaks down software development into a set of manageable and linked techniques which are combined to make a productive whole. In addition, it can be used as a natural communication medium which avoids the idiosyncracies of particular implementationlanguages, and through CASE tool support can act as an effective and efficient consistency checker.
Various aspect-oriented languages, e.g., AspectJ, Aspect- Werkz, and JAsCo, have been proposed as extensions to one particular object-oriented base language, namely Java. But these extensions do not fully take the int...
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A general class of program analyses are a combination of context-free and regular language reachability. We define regularly annotated set constraints, a constraint formalism that captures this class. Our results exte...
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A general class of program analyses are a combination of context-free and regular language reachability. We define regularly annotated set constraints, a constraint formalism that captures this class. Our results extend the class of reachability problems expressible naturally in a single constraint formalism, including such diverse applications as interprocedural dataflow analysis, precise type-based flow analysis, and pushdown model checking.
We show how to programmatically model processes that humans use when extracting answers to queries (e.g., "Who invented typewriter?", "List of Washington national parks") from semi-structured Web p...
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ISBN:
(纸本)9781450329569
We show how to programmatically model processes that humans use when extracting answers to queries (e.g., "Who invented typewriter?", "List of Washington national parks") from semi-structured Web pages returned by a search engine. This modeling enables various applications including automating repetitive search tasks, and helping search engine developers design micro-segments of factoid questions. We describe the design and implementation of a domain-specific language that enables extracting data from a webpage based on its structure, visual layout, and linguistic patterns. We also describe an algorithm to rank multiple answers extracted from multiple webpages. On 100,000+ queries (across 7 micro-segments) obtained from Bing logs, our system LASEWEB answered queries with an average recall of 71%. Also, the desired answer(s) were present in top-3 suggestions for 95%+ cases.
This paper describes a computer architecture, Spatial Computation (SC), which is based on the translation of high-level language programs directly into hardware structures. SC program implementations are completely di...
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This paper describes a computer architecture, Spatial Computation (SC), which is based on the translation of high-level language programs directly into hardware structures. SC program implementations are completely distributed, with no centralized control. SC circuits are optimized for wires at the expense of computation units. In this paper we investigate a particular implementation of SC: ASH (Application-Specific Hardware). Under the assumption that computation is cheaper than communication, ASH replicates computation units to simplify interconnect, building a system which uses very simple, completely dedicated communication channels. As a consequence, communication on the datapath never requires arbitration;the only arbitration required is for accessing memory. ASH relies on very simple hardware primitives, using no associative structures, no multiported register files, no scheduling logic, no broadcast, and no clocks. As a consequence, ASH hardware is fast and extremely power efficient. In this work we demonstrate three features of ASH: (1) that such architectures can be built by automatic compilation of C programs;(2) that distributed computation is in some respects fundamentally different from monolithic superscalar processors;and (3) that ASIC implementations of ASH use three orders of magnitude less energy compared to high-end superscalar processors, while being on average only 33% slower in performance (3.5x worst-case).
Cache miss stalls hurt performance because of the large gap between memory and processor speeds - for example, the popular server benchmark SPEC JBB2000 spends 45% of its cycles stalled waiting for memory requests on ...
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Cache miss stalls hurt performance because of the large gap between memory and processor speeds - for example, the popular server benchmark SPEC JBB2000 spends 45% of its cycles stalled waiting for memory requests on the Itanium(R) 2 processor. Traversing linked data structures causes a large portion of these stalls. Prefetching for linked data structures remains a major challenge because serial data dependencies between elements in a linked data structure preclude the timely materialization of prefetch addresses. This paper presents Mississippi Delta (MS Delta), a novel technique for prefetching linked data structures that closely integrates the hardware performance monitor (HPM), the garbage collector's global view of heap and object layout, the type-level metadata inherent in type-safe programs, and JIT compiler analysis. The garbage collector uses the HPM's data cache miss information to identify cache miss intensive traversal paths through linked data structures, and then discovers regular distances (deltas) between these linked objects. JIT compiler analysis injects prefetch instructions using deltas to materialize prefetch addresses. We have implemented MS Delta in a fully dynamic profile-guided optimization system: the StarJIT dynamic compiler [1] and the ORP Java virtual machine [9]. We demonstrate a 28-29% reduction in stall cycles attributable to the high-latency cache misses targeted by MS Delta and a speedup of 11-14% on the cache miss intensive SPEC JBB2000 benchmark.
作者：
Birka, AErnst, MDMIT
Comp Sci & Artificial Intelligence Lab Cambridge MA 02139 USA
This paper describes a type system that is capable of expressing and enforcing immutability constraints. The specific constraint expressed is that the abstract state of the object to which an immutable reference refer...
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This paper describes a type system that is capable of expressing and enforcing immutability constraints. The specific constraint expressed is that the abstract state of the object to which an immutable reference refers cannot be modified using that reference. The abstract state is (part of) the transitively reachable state: that is, the state of the object and all state reachable from it by following references. The type system permits explicitly excluding fields or objects from the abstract state of an object. For a statically type-safe language, the type system guarantees reference immutability. If the language is extended with immutability downcasts, then run-time checks enforce the reference immutability constraints. In order to better understand the usability and efficacy of the type system, we have implemented an extension to Java, called Javari, that includes all the features of our type system. Javari is interoperable with Java and existing JVMs. It can be viewed as a proposal for the semantics of the Java const keyword, though Javari's syntax uses readonly instead. This paper describes the design and implementation of Javari, including the type-checking rules for the language. This paper also discusses experience with 160,000 lines of Javari code. Javari was easy to use and provided a number of benefits, including detecting errors in well-tested code.
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