24 research outputs found
Optimizing pointer linked data structures
The thesis explores different ways of optimizing pointer linked data
structures, and especially restructuring them. The mechanisms are based
on compiler technology, theory, computer languages and hardware
architecture that are capable of optimizing the memory layout of complex
pointer linked data structures.Computer Systems, Imagery and Medi
Customizing the Computation Capabilities of Microprocessors.
Designers of microprocessor-based systems must constantly improve
performance and increase computational efficiency in their designs to
create value. To this end, it is increasingly common to see
computation accelerators in general-purpose processor
designs. Computation accelerators collapse portions of an
application's dataflow graph, reducing the critical path of
computations, easing the burden on processor resources, and reducing
energy consumption in systems. There are many problems associated with
adding accelerators to microprocessors, though. Design of
accelerators, architectural integration, and software support all
present major challenges.
This dissertation tackles these challenges in the context of
accelerators targeting acyclic and cyclic patterns of
computation. First, a technique to identify critical computation
subgraphs within an application set is presented. This technique is
hardware-cognizant and effectively generates a set of instruction set
extensions given a domain of target applications. Next, several
general-purpose accelerator structures are quantitatively designed
using critical subgraph analysis for a broad application set.
The next challenge is architectural integration of
accelerators. Traditionally, software invokes accelerators by
statically encoding new instructions into the application binary. This
is incredibly costly, though, requiring many portions of hardware and
software to be redesigned. This dissertation develops strategies to
utilize accelerators, without changing the instruction set. In the
proposed approach, the microarchitecture translates applications at
run-time, replacing computation subgraphs with microcode to utilize
accelerators. We explore the tradeoffs in performing difficult aspects
of the translation at compile-time, while retaining run-time
replacement. This culminates in a simple microarchitectural interface
that supports a plug-and-play model for integrating accelerators into
a pre-designed microprocessor.
Software support is the last challenge in dealing with computation
accelerators. The primary issue is difficulty in generating
high-quality code utilizing accelerators. Hand-written assembly code
is standard in industry, and if compiler support does exist, simple
greedy algorithms are common. In this work, we investigate more
thorough techniques for compiling for computation accelerators. Where
greedy heuristics only explore one possible solution, the techniques
in this dissertation explore the entire design space, when
possible. Intelligent pruning methods ensure that compilation is both
tractable and scalable.Ph.D.Computer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/57633/2/ntclark_1.pd
Optimal Global Instruction Scheduling for the Itanium® Processor Architecture
On the Itanium 2 processor, effective global instruction scheduling is crucial to high performance. At the same time, it poses a challenge to the compiler: This code generation subtask involves strongly interdependent decisions and complex trade-offs that are difficult to cope with for heuristics. We tackle this NP-complete problem with integer linear programming (ILP), a search-based method that yields provably optimal results. This promises faster code as well as insights into the potential of the architecture. Our ILP model comprises global code motion with compensation copies, predication, and Itanium-specific features like control/data speculation. In integer linear programming, well-structured models are the key to acceptable solution times. The feasible solutions of an ILP are represented by integer points inside a polytope. If all vertices of this polytope are integral, then the ILP can be solved in polynomial time. We define two subproblems of global scheduling in which some constraint classes are omitted and show that the corresponding two subpolytopes of our ILP model are integral and polynomial sized. This substantiates that the found model is of high efficiency, which is also confirmed by the reasonable solution times. The ILP formulation is extended by further transformations like cyclic code motion, which moves instructions upwards out of a loop, circularly in the opposite direction of the loop backedges. Since the architecture requires instructions to be encoded in fixed-sized bundles of three, a bundler is developed that computes bundle sequences of minimal size by means of precomputed results and dynamic programming. Experiments have been conducted with a postpass tool that implements the ILP scheduler. It parses assembly procedures generated by Intel�s Itanium compiler and reschedules them as a whole. Using this tool, we optimize a selection of hot functions from the SPECint 2000 benchmark. The results show a significant speedup over the original code.Globale Instruktionsanordnung hat beim Itanium-2-Prozessor großen
Einfluß auf die Leistung und stellt dabei gleichzeitig eine Herausforderung
für den Compiler dar: Sie ist mit zahlreichen komplexen, wechselseitig
voneinander abhängigen Entscheidungen verbunden, die für Heuristiken
nur schwer zu beherrschen sind.Wir lösen diesesNP-vollständige
Problem mit ganzzahliger linearer Programmierung (ILP), einer suchbasierten
Methode mit beweisbar optimalen Ergebnissen. Das ermöglicht
neben schnellerem Code auch Einblicke in das Potential der Itanium-
Prozessorarchitektur. Unser ILP-Modell umfaßt globale Codeverschiebungen
mit Kompensationscode, Prädikation und Itanium-spezifische
Techniken wie Kontroll- und Datenspekulation.
Bei ganzzahliger linearer Programmierung sind wohlstrukturierte
Modelle der Schlüssel zu akzeptablen Lösungszeiten. Die zulässigen Lösungen
eines ILPs werden durch ganzzahlige Punkte innerhalb eines
Polytops repräsentiert. Sind die Eckpunkte dieses Polytops ganzzahlig,
kann das ILP in Polynomialzeit gelöst werden. Wir definieren zwei Teilprobleme
globaler Instruktionsanordnung durch Auslassung bestimmter
Klassen von Nebenbedingungen und beweisen, daß die korrespondierenden
Teilpolytope unseres ILP-Modells ganzzahlig und von polynomieller
Größe sind. Dies untermauert die hohe Effizienz des gefundenen Modells,
die auch durch moderate Lösungszeiten bestätigt wird.
Das ILP-Modell wird um weitere Transformationen wie zyklische Codeverschiebung
erweitert; letztere bezeichnet das Verschieben von Befehlen
aufwärts aus einer Schleife heraus, in Gegenrichtung ihrer Rückwärtskanten.
Da die Architektur eine Kodierung der Befehle in Dreierbündeln
fester Größe vorschreibt, wird ein Bundler entwickelt, der Bündelsequenzen
minimaler Länge mit Hilfe vorberechneter Teilergebnisse und dynamischer
Programmierung erzeugt.
Für die Experimente wurde ein Postpassoptimierer erstellt. Er liest
von Intels Itanium-Compiler erzeugte Assemblerroutinen ein und ordnet
die enthaltenen Instruktionen mit Hilfe der ILP-Methode neu an. Angewandt
auf eine Auswahl von Funktionen aus dem Benchmark SPECint
2000 erreicht der Optimierer eine signifikante Beschleunigung gegenüber
dem Originalcode
Optimal Global Instruction Scheduling for the Itanium® Processor Architecture
On the Itanium 2 processor, effective global instruction scheduling is crucial to high performance. At the same time, it poses a challenge to the compiler: This code generation subtask involves strongly interdependent decisions and complex trade-offs that are difficult to cope with for heuristics. We tackle this NP-complete problem with integer linear programming (ILP), a search-based method that yields provably optimal results. This promises faster code as well as insights into the potential of the architecture. Our ILP model comprises global code motion with compensation copies, predication, and Itanium-specific features like control/data speculation. In integer linear programming, well-structured models are the key to acceptable solution times. The feasible solutions of an ILP are represented by integer points inside a polytope. If all vertices of this polytope are integral, then the ILP can be solved in polynomial time. We define two subproblems of global scheduling in which some constraint classes are omitted and show that the corresponding two subpolytopes of our ILP model are integral and polynomial sized. This substantiates that the found model is of high efficiency, which is also confirmed by the reasonable solution times. The ILP formulation is extended by further transformations like cyclic code motion, which moves instructions upwards out of a loop, circularly in the opposite direction of the loop backedges. Since the architecture requires instructions to be encoded in fixed-sized bundles of three, a bundler is developed that computes bundle sequences of minimal size by means of precomputed results and dynamic programming. Experiments have been conducted with a postpass tool that implements the ILP scheduler. It parses assembly procedures generated by Intel�s Itanium compiler and reschedules them as a whole. Using this tool, we optimize a selection of hot functions from the SPECint 2000 benchmark. The results show a significant speedup over the original code.Globale Instruktionsanordnung hat beim Itanium-2-Prozessor großen
Einfluß auf die Leistung und stellt dabei gleichzeitig eine Herausforderung
für den Compiler dar: Sie ist mit zahlreichen komplexen, wechselseitig
voneinander abhängigen Entscheidungen verbunden, die für Heuristiken
nur schwer zu beherrschen sind.Wir lösen diesesNP-vollständige
Problem mit ganzzahliger linearer Programmierung (ILP), einer suchbasierten
Methode mit beweisbar optimalen Ergebnissen. Das ermöglicht
neben schnellerem Code auch Einblicke in das Potential der Itanium-
Prozessorarchitektur. Unser ILP-Modell umfaßt globale Codeverschiebungen
mit Kompensationscode, Prädikation und Itanium-spezifische
Techniken wie Kontroll- und Datenspekulation.
Bei ganzzahliger linearer Programmierung sind wohlstrukturierte
Modelle der Schlüssel zu akzeptablen Lösungszeiten. Die zulässigen Lösungen
eines ILPs werden durch ganzzahlige Punkte innerhalb eines
Polytops repräsentiert. Sind die Eckpunkte dieses Polytops ganzzahlig,
kann das ILP in Polynomialzeit gelöst werden. Wir definieren zwei Teilprobleme
globaler Instruktionsanordnung durch Auslassung bestimmter
Klassen von Nebenbedingungen und beweisen, daß die korrespondierenden
Teilpolytope unseres ILP-Modells ganzzahlig und von polynomieller
Größe sind. Dies untermauert die hohe Effizienz des gefundenen Modells,
die auch durch moderate Lösungszeiten bestätigt wird.
Das ILP-Modell wird um weitere Transformationen wie zyklische Codeverschiebung
erweitert; letztere bezeichnet das Verschieben von Befehlen
aufwärts aus einer Schleife heraus, in Gegenrichtung ihrer Rückwärtskanten.
Da die Architektur eine Kodierung der Befehle in Dreierbündeln
fester Größe vorschreibt, wird ein Bundler entwickelt, der Bündelsequenzen
minimaler Länge mit Hilfe vorberechneter Teilergebnisse und dynamischer
Programmierung erzeugt.
Für die Experimente wurde ein Postpassoptimierer erstellt. Er liest
von Intels Itanium-Compiler erzeugte Assemblerroutinen ein und ordnet
die enthaltenen Instruktionen mit Hilfe der ILP-Methode neu an. Angewandt
auf eine Auswahl von Funktionen aus dem Benchmark SPECint
2000 erreicht der Optimierer eine signifikante Beschleunigung gegenüber
dem Originalcode
Abstracts on Radio Direction Finding (1899 - 1995)
The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography).
Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM.
The contents of these files are:
1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format];
2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format];
3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion
Evolutionary Computation 2020
Intelligent optimization is based on the mechanism of computational intelligence to refine a suitable feature model, design an effective optimization algorithm, and then to obtain an optimal or satisfactory solution to a complex problem. Intelligent algorithms are key tools to ensure global optimization quality, fast optimization efficiency and robust optimization performance. Intelligent optimization algorithms have been studied by many researchers, leading to improvements in the performance of algorithms such as the evolutionary algorithm, whale optimization algorithm, differential evolution algorithm, and particle swarm optimization. Studies in this arena have also resulted in breakthroughs in solving complex problems including the green shop scheduling problem, the severe nonlinear problem in one-dimensional geodesic electromagnetic inversion, error and bug finding problem in software, the 0-1 backpack problem, traveler problem, and logistics distribution center siting problem. The editors are confident that this book can open a new avenue for further improvement and discoveries in the area of intelligent algorithms. The book is a valuable resource for researchers interested in understanding the principles and design of intelligent algorithms
Evolutionary Computation
This book presents several recent advances on Evolutionary Computation, specially evolution-based optimization methods and hybrid algorithms for several applications, from optimization and learning to pattern recognition and bioinformatics. This book also presents new algorithms based on several analogies and metafores, where one of them is based on philosophy, specifically on the philosophy of praxis and dialectics. In this book it is also presented interesting applications on bioinformatics, specially the use of particle swarms to discover gene expression patterns in DNA microarrays. Therefore, this book features representative work on the field of evolutionary computation and applied sciences. The intended audience is graduate, undergraduate, researchers, and anyone who wishes to become familiar with the latest research work on this field
Combining SOA and BPM Technologies for Cross-System Process Automation
This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation