The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Ralf S Engelschall - One of the best experts on this subject based on the ideXlab platform.
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portable multiThreading the signal stack trick for user space Thread Creation
USENIX Annual Technical Conference, 2000Co-Authors: Ralf S EngelschallAbstract:This paper describes a pragmatic but portable fallback approach for creating and dispatching between the machine contexts of multiple Threads of execution on Unix systems that lack a dedicated user-space context switching facility. Such a fallback approach for implementing machine contexts is a vital part of a user-space multiThreading environment, if it has to achieve maximum portability across a wide range of Unix flavors. The approach is entirely based on standard Unix system facilities and ANSI-C language features and especially does not require any assembly code or platform specific tricks at all. The most interesting issue is the technique of creating the machine context for Threads, which this paper explains in detail. The described approach closely follows the algorithm as implemented by the author for the popular user-space multiThreading library GNU Portable Threads (GNU Pth, [25]) which this way quickly gained the status of one of the most portable user-space multiThreading libraries.
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the signal stack trick for user space Thread Creation
2000Co-Authors: Portable Multithreading, Ralf S EngelschallAbstract:This paper describes a pragmatic but portable fallback approach for creating and dispatching between the machine contexts of multiple Threads of execution on Unix systems that lack a dedicated user-space context switching facility. Such a fallback approach for implementing machine contexts is a vital part of a user-space multiThreading environment, if it has to achieve maximum portability across a wide range of Unix flavors. The approach is entirely based on standard Unix system facilities and ANSI-C language features and especially does not require any assembly code or platform specific tricks at all. The most interesting issue is the technique of creating the machine context for Threads, which this paper explains in detail. The described approach closely follows the algorithm as implemented by the author for the popular user-space multiThreading library GNU Portable Threads (GNU Pth, [25]) which this way quickly gained the status of one of the most portable user-space multiThreading libraries.
Akinori Yonezawa - One of the best experts on this subject based on the ideXlab platform.
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performance evaluation of openmp applications with nested parallelism
Lecture Notes in Computer Science, 2000Co-Authors: Yoshizumi Tanaka, Kenjiro Taura, Mitsuhisa Sato, Akinori YonezawaAbstract:Many existing OpenMP systems do not sufficiently implement nested parallelism. This is supposedly because nested parallelism is believed to require a significant implementation effort, incur a large overhead, or lack applications. This paper demonstrates Omni/ST, a simple and efficient implementation of OpenMP nested parallelism using StackThreads/MP, which is a fine-grain Thread library. Thanks to StackThreads/MP, OpenMP parallel constructs are simply mapped onto Thread Creation primitives of StackThreads/MP, yet they are efficiently managed with a fixed number of Threads in the underlying Thread package (e.g., PThreads). Experimental results on Sun Ultra Enterprise 10000 with up to 60 processors show that overhead imposed by nested parallelism is very small (1-3% in five out of six applications, and 8% for the other), and there is a significant scalability benefit for applications with nested parallelism.
Peter Lammich - One of the best experts on this subject based on the ideXlab platform.
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Iterable Forward Reachability Analysis of Monitor-DPNs
2016Co-Authors: A. Banerjee, Peter Lammich, O. Danvy, -g. K. Doh, J. Hatcliff, Benedikt Nordhoff, Markus Müller-olm, Fakultät Für Informatik, Tu MünchenAbstract:There is a close connection between data-flow analysis and model checking as observed and stud-ied in the nineties by Steffen and Schmidt. This indicates that automata-based analysis techniques developed in the realm of infinite-state model checking can be applied as data-flow analyzers that interpret complex control structures, which motivates the development of such analysis techniques for ever more complex models. One approach proposed by Esparza and Knoop is based on com-putation of predecessor or successor sets for sets of automata configurations. Our goal is to adapt and exploit this approach for analysis of multi-Threaded Java programs. Specifically, we consider the model of Monitor-DPNs for concurrent programs. Monitor-DPNs precisely model unbounded recur-sion, dynamic Thread Creation, and synchronization via well-nested locks with finite abstractions of procedure- and Thread-local state. Previous work on this model showed how to compute regular pre-decessor sets of regular configurations and tree-regular successor sets of a fixed initial configuration. By combining and extending different previously developed techniques we show how to compute tree-regular successor sets of tree-regular sets. Thereby we obtain an iterable, lock-sensitive forward reachability analysis. We implemented the analysis for Java programs and applied it to information flow control and data race detection.
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conflict analysis of programs with procedures dynamic Thread Creation and monitors
Static Analysis Symposium, 2008Co-Authors: Peter Lammich, Markus MullerolmAbstract:We study conflict detection for programs with procedures, dynamic Thread Creation and a fixed finite set of (reentrant) monitors. We show that deciding the existence of a conflict is NP-complete for our model (that abstracts guarded branching by nondeterministic choice) and present a fixpoint-based complete conflict detection algorithm. Our algorithm needs worst-case exponential time in the number of monitors, but is linear in the program size.
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precise fixpoint based analysis of programs with Thread Creation and procedures
International Conference on Concurrency Theory, 2007Co-Authors: Peter Lammich, Markus MullerolmAbstract:We present a fixpoint-based algorithm for context-sensitive interprocedural kill/gen-analysis of programs with Thread Creation. Our algorithm is precise up to abstraction of synchronization common in this line of research; it can handle forward as well as backward problems. We exploit a structural property of kill/gen-problems that allows us to analyze the influence of environment actions independently from the local transfer of data flow information. While this idea has been used for programs with parbegin/parend blocks before in work of Knoop/Steffen/Vollmer and Seidl/Steffen, considerable refinement and modification is needed to extend it to Thread Creation, in particular for backward problems. Our algorithm computes annotations for all program points in time depending linearly on the program size, thus being faster than a recently proposed automata based algorithm by Bouajjani et. al..
Haoxian Zhao - One of the best experts on this subject based on the ideXlab platform.
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boom taking boolean program model checking one step further
Tools and Algorithms for Construction and Analysis of Systems, 2010Co-Authors: Gerard Basler, Daniel Kroening, Matthew Hague, Thomas Wahl, Haoxian ZhaoAbstract:We present Boom, a comprehensive analysis tool for Boolean programs. We focus in this paper on model-checking non-recursive concurrent programs. Boom implements a recent variant of counter abstraction, where Thread counters are used in a program-context aware way. While designed for bounded counters, this method also integrates well with the Karp-Miller tree construction for vector addition systems, resulting in a reachability engine for programs with unbounded Thread Creation. The concurrent version of Boom is implemented using BDDs and includes partial order reduction methods. Boom is intended for model checking system-level code via predicate abstraction. We present experimental results for the verification of Boolean device driver models.
Markus Mullerolm - One of the best experts on this subject based on the ideXlab platform.
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conflict analysis of programs with procedures dynamic Thread Creation and monitors
Static Analysis Symposium, 2008Co-Authors: Peter Lammich, Markus MullerolmAbstract:We study conflict detection for programs with procedures, dynamic Thread Creation and a fixed finite set of (reentrant) monitors. We show that deciding the existence of a conflict is NP-complete for our model (that abstracts guarded branching by nondeterministic choice) and present a fixpoint-based complete conflict detection algorithm. Our algorithm needs worst-case exponential time in the number of monitors, but is linear in the program size.
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precise fixpoint based analysis of programs with Thread Creation and procedures
International Conference on Concurrency Theory, 2007Co-Authors: Peter Lammich, Markus MullerolmAbstract:We present a fixpoint-based algorithm for context-sensitive interprocedural kill/gen-analysis of programs with Thread Creation. Our algorithm is precise up to abstraction of synchronization common in this line of research; it can handle forward as well as backward problems. We exploit a structural property of kill/gen-problems that allows us to analyze the influence of environment actions independently from the local transfer of data flow information. While this idea has been used for programs with parbegin/parend blocks before in work of Knoop/Steffen/Vollmer and Seidl/Steffen, considerable refinement and modification is needed to extend it to Thread Creation, in particular for backward problems. Our algorithm computes annotations for all program points in time depending linearly on the program size, thus being faster than a recently proposed automata based algorithm by Bouajjani et. al..
