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Incrementalization across object abstraction

acm sigplan NOTICES 2005年第10期40卷 473-486页

作者： Liu, YA Stoller, SD Gorbovitski, M Rothamel, T Liu, YE SUNY Stony Brook Dept Comp Sci Stony Brook NY 11794 USA Univ Manitoba Dept Comp Sci Winnipeg MB R3T 2N2 Canada

Object abstraction supports the separation of what operations are provided by systems and components from how the operations are implemented, and is essential in enabling the construction of complex systems from components. Unfortunately, clear and modular implementations have poor performance when expensive query operations are repeated, while efficient implementations that incrementally maintain these query results are much more difficult to develop and to understand, because the code blows up significantly, and is no longer clear or modular. This paper describes a powerful and systematic method that first allows the "what" of each component to be specified in a clear and modular fashion and implemented straightforwardly in an object-oriented language;then analyzes the queries and updates, across object abstraction, in the straightforward implementation: and finally derives the sophisticated and efficient "how;, of each component by incrementally maintaining the results of repeated expensive queries with respect to updates to their parameters. Our implementation and experimental results for example applications in query optimization, role-based access control, etc. demonstrate tire effectiveness and benefit of the method.

关键词： design languages performance abstraction design program transformation incrementalization invariants program analysis program optimization object-oriented

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Experience with CST: programming and implementation 89

Experience with CST: programming and implementation

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Proceedings of the acm sigplan 1989 conference on programming language design and implementation

作者： W. Horwat A. A. Chien W. J. Dally Artificial Intelligence Laboratory and Laboratory for Computer Science Massachusetts Institute of Technology Cambridge Massachusetts

ISBN: (纸本)9780897913065

CST is a programming language based on Smalltalk-802 that supports concurrency using locks, asynchronous messages, and distributed objects. In this paper, we describe CST: the language and its implementation. Example programs and initial programming experience with CST are described. Our implementation of CST generates native code for the J-machine, a fine-grained concurrent computer. Some compiler optimizations developed in conjunction with that implementation are also described.

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Implicit Invocation Meets Safe, Implicit Concurrency

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acm sigplan NOTICES 2011年第2期46卷 63-72页

作者： Long, Yuheng Mooney, Sean L. Sondag, Tyler Rajan, Hridesh Iowa State Univ Dept Comp Sci Ames IA 50011 USA

Writing correct and efficient concurrent programs still remains a challenge. Explicit concurrency is difficult, error prone, and creates code which is hard to maintain and debug. This type of concurrency also treats modular program design and concurrency as separate goals, where modularity often suffers. To solve these problems, we are designing a new language that we call Panini. In this paper, we focus on Panini's asynchronous, typed events which reconcile the modularity goal promoted by the implicit invocation design style with the concurrency goal of exposing potential concurrency between the execution of subjects and observers. Since modularity is improved and concurrency is implicit in Panini, programs are easier to reason about and maintain. The language incorporates a static analysis to determine potential conflicts between handlers and a dynamic analysis which uses the conflict information to determine a safe order for handler invocation. This mechanism avoids races and deadlocks entirely, yielding programs with a guaranteed deterministic semantics. To evaluate our language design and implementation we show several examples of its usage as well as an empirical study of program performance. We found that not only is developing and understanding Panini programs significantly easier compared to standard concurrent object-oriented programs, but also performance of Panini programs is comparable to their equivalent hand-tuned versions written using Java's fork-join framework.

关键词： languages design Performance Safe Implicit Concurrency Modularity

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Customization: optimizing compiler technology for SELF, a dynamically-typed object-oriented programming language

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sigplan Notices (acm Special Interest Group on programming languages) 1989年第7期24卷 146-160页

作者： Chambers, Craig Ungar, David Stanford Univ United States

Dynamically-typed object-oriented languages please programmers, but their lack of static type information penalizes performance. Our new implementation techniques extract static type information from declaration-free programs. Our system compliles several copies of a given procedure, each customized for one receiver type, so that the type of the receiver is bound at compile time. The compiler predicts types that are statically unknown but likely, and inserts run-time type tests to verify its predictions. It splits calls, compiling a copy on each control path, optimized to the specific types on that path. Coupling these new techniques with compile-time message lookup, aggressive procedure inlining, and traditional optimizations has doubled the performance of dynamically-typed object-oriented languages.

关键词： Computer programming languages

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Isolation for Nested Task Parallelism

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acm sigplan NOTICES 2013年第10期48卷 571-587页

作者： Zhao, Jisheng Lublinerman, Roberto Budimlic, Zoran Chaudhuri, Swarat Sarkar, Vivek Rice Univ Houston TX 77251 USA Google Inc Mountain View CA USA

Isolation-the property that a task can access shared data without interference from other tasks-is one of the most basic concerns in parallel programming. While there is a large body of past work on isolated task-parallelism, the integration of isolation, task-parallelism, and nesting of tasks has been a difficult and unresolved challenge. In this paper, we present a programming and execution model called Otello where isolation is extended to arbitrarily nested parallel tasks with irregular accesses to heap data. At the same time, no additional burden is imposed on the programmer, who only exposes parallelism by creating and synchronizing parallel tasks, leaving the job of ensuring isolation to the underlying compiler and runtime system. Otello extends our past work on Aida execution model and the delegated isolation mechanism [22] to the setting of nested parallelism. The basic runtime construct in Aida and Otello is an assembly: a task equipped with a region in the shared heap that it owns. When an assembly A conflicts with an assembly B, A transfers-or delegates-its code and owned region to a carefully selected assembly C in a way that will ensure isolation with B, leaving the responsibility of re-executing task A to C. The choice of C depends on the nesting relationship between A and B. We have implemented Otello on top of the Habanero Java (HJ) parallel programming language [8], and used this implementation to evaluate Otello on collections of nested task-parallel benchmarks and non-nested transactional benchmarks from past work. On the nested task-parallel bench-marks, Otello achieves scalability comparable to HJ programs without built-in isolation, and the relative overhead of Otello is lower than that of many published data-race detection algorithms that detect the isolation violations (but do not enforce isolation). For the transactional benchmarks, Otello incurs lower overhead than a state-of-the-art software transactional memory system (Deuce STM).

关键词： languages design Isolation programming abstractions Irregular parallelism Contention

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Automatic generation of DAG parallelism

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sigplan Notices (acm Special Interest Group on programming languages) 1989年第7期24卷 54-68页

作者： Cytron, Ron Hind, Michael Hsieh, Wilson IBM T.J. Watson Research Cent United States

We present an algorithm for automatically generating a nested, fork-join parallel program from a sequential program represented in terms of control and data dependences. This algorithm embodies two techniques for dealing with data dependences: the first implicitly satisfies such dependences by reducing parallelism, and the second eliminates some dependences by introducing private variables. This algorithm has been implemented in the PTRAN system.

关键词： Computer programming languages

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Process decomposition through locality of reference

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sigplan Notices (acm Special Interest Group on programming languages) 1989年第7期24卷 69-80页

作者： Rogers, Anne Pingali, Keshav Cornell Univ United States

In the context of sequential computers, it is common practice to exploit temporal locality of reference through devices such as caches and virtual memory. In the context of multiprocessors, we believe that it is equally important to exploit spatial locality of reference. We are developing a system which, given a sequential program and its domain decomposition, performs process decomposition so as to enhance spatial locality of reference. We describe an application of this method - generating code from shared-memory programs for the (distributed memory) Intel iPSC/2.

关键词： Computer programming languages

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Technique for summarizing data access and its use in parallelism enhancing transformations

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sigplan Notices (acm Special Interest Group on programming languages) 1989年第7期24卷 41-53页

作者： Balasundaram, Vasanth Kennedy, Ken Rice Univ United States

In this paper, we present a technique for summarizing the data accesses in a given region and show how this summary can be used to detect and enhance task parallelism in a program. For the sake of simplicity, we restrict our discussion to Fortran programs that consist of a sequence of perfectly-nested loops in which all subroutine calls are expanded inline. However, the techniques presented here can easily be extended to the general case of programs with imperfectly nested loops and subroutine calls.

关键词： Computer programming languages

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Automatic volume management for programmable microfluidics

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acm sigplan NOTICES 2008年第6期43卷 56-67页

作者： Amin, Ahmed M. Thottethodi, Mithuna Vijaykumar, T. N. Wereley, Steven Jacobson, Stephen C. Purdue Univ Sch Elect & Comp Engn W Lafayette IN 47907 USA Purdue Univ Sch Mech Engn W Lafayette IN 47907 USA Indiana Univ Dept Chem Bloomington IN 47405 USA

Microfluidics has enabled lab-on-a-chip technology to miniaturize and integrate biological and chemical analyses to a single chip comprising channels, valves, mixers, heaters, separators, and sensors. Recent papers have proposed programmable labs-on-a-chip as an alternative to traditional application-specific chips to reduce design effort, time, and cost. While these previous papers provide the basic support for programmability, this paper identifies and addresses a practical issue, namely, fluid volume management. Volume management addresses the problem that the use of a fluid depletes it and unless the given volume of a fluid is distributed carefully among all its uses, execution may run out of the fluid before all its uses are complete. Additionally, fluid volumes should not overflow (i.e., exceed hardware capacity) or underflow (i.e., fall below hardware resolution). We show that the problem can be formulated as a linear programming problem ( LP). Because LP's complexity and slow execution times in practice may be a concern, we propose another approach, called DAGSolve, which over-constrains the problem to achieve linear complexity while maintaining good solution quality. We also propose two optimizations, called cascading and static replication, to handle cases involving extreme mix ratios and numerous fluid uses which may defeat both LP and DAGSolve. Using some real-world assays, we show that our techniques produce good solutions while being faster than LP.

关键词： algorithms design microfluidics programmable lab-on-a-chip fluid volume management

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End-to-End Verification of Information-Flow Security for C and Assembly Programs

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acm sigplan NOTICES 2016年第6期51卷 648-664页

作者： Costanzo, David Shao, Zhong Gu, Ronghui Yale Univ New Haven CT 06520 USA

Protecting the confidentiality of information manipulated by a computing system is one of the most important challenges facing today's cybersecurity community. A promising step toward conquering this challenge is to formally verify that the end-to-end behavior of the computing system really satisfies various information-flow policies. Unfortunately, because today's system software still consists of both C and assembly programs, the end-to-end verification necessarily requires that we not only prove the security properties of individual components, but also carefully preserve these properties through compilation and cross-language linking. In this paper, we present a novel methodology for formally verifying end-to-end security of a software system that consists of both C and assembly programs. We introduce a general definition of observation function that unifies the concepts of policy specification, state indistinguishability, and whole-execution behaviors. We show how to use different observation functions for different levels of abstraction, and how to link different security proofs across abstraction levels using a special kind of simulation that is guaranteed to preserve state indistinguishability. To demonstrate the effectiveness of our new methodology, we have successfully constructed an end-to-end security proof, fully formalized in the Coq proof assistant, of a nontrivial operating system kernel (running on an extended CompCert x86 assembly machine model). Some parts of the kernel are written in C and some are written in assembly;we verify all of the code, regardless of language.

关键词： Verification Security Reliability languages design Information Flow Control Security Policy Specification Security-Preserving Simulation Program Verification Certified OS Kernels

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