Smalltalk Solutions 2008 Report, ESUG 2008 Report, VAS Report
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Events, Co-Routines, Continuations and Threads OS (And Application)Execution Models System Building
Events, Co-routines, Continuations and Threads OS (and application)Execution Models System Building General purpose systems need to deal with • Many activities – potentially overlapping – may be interdependent • Activities that depend on external phenomena – may requiring waiting for completion (e.g. disk read) – reacting to external triggers (e.g. interrupts) Need a systematic approach to system structuring © Kevin Elphinstone 2 Construction Approaches Events Coroutines Threads Continuations © Kevin Elphinstone 3 Events External entities generate (post) events. • keyboard presses, mouse clicks, system calls Event loop waits for events and calls an appropriate event handler. • common paradigm for GUIs Event handler is a function that runs until completion and returns to the event loop. © Kevin Elphinstone 4 Event Model The event model only requires a single stack Memory • All event handlers must return to the event loop CPU Event – No blocking Loop – No yielding PC Event SP Handler 1 REGS Event No preemption of handlers Handler 2 • Handlers generally short lived Event Handler 3 Data Stack © Kevin Elphinstone 5 What is ‘a’? int a; /* global */ int func() { a = 1; if (a == 1) { a = 2; } No concurrency issues within a return a; handler } © Kevin Elphinstone 6 Event-based kernel on CPU with protection Kernel-only Memory User Memory CPU Event Loop Scheduling? User PC Event Code SP Handler 1 REGS Event Handler 2 User Event Data Handler 3 Huh? How to support Data Stack multiple Stack processes? © Kevin Elphinstone 7 Event-based kernel on CPU with protection Kernel-only Memory User Memory CPU PC Trap SP Dispatcher User REGS Event Code Handler 1 User-level state in PCB Event PCB Handler 2 A User Kernel starts on fresh Timer Event Data stack on each trap (Scheduler) PCB B No interrupts, no blocking Data Current in kernel mode Thead PCB C Stack Stack © Kevin Elphinstone 8 Co-routines Originally described in: • Melvin E. -
Designing an Ultra Low-Overhead Multithreading Runtime for Nim
Designing an ultra low-overhead multithreading runtime for Nim Mamy Ratsimbazafy Weave [email protected] https://github.com/mratsim/weave Hello! I am Mamy Ratsimbazafy During the day blockchain/Ethereum 2 developer (in Nim) During the night, deep learning and numerical computing developer (in Nim) and data scientist (in Python) You can contact me at [email protected] Github: mratsim Twitter: m_ratsim 2 Where did this talk came from? ◇ 3 years ago: started writing a tensor library in Nim. ◇ 2 threading APIs at the time: OpenMP and simple threadpool ◇ 1 year ago: complete refactoring of the internals 3 Agenda ◇ Understanding the design space ◇ Hardware and software multithreading: definitions and use-cases ◇ Parallel APIs ◇ Sources of overhead and runtime design ◇ Minimum viable runtime plan in a weekend 4 Understanding the 1 design space Concurrency vs parallelism, latency vs throughput Cooperative vs preemptive, IO vs CPU 5 Parallelism is not 6 concurrency Kernel threading 7 models 1:1 Threading 1 application thread -> 1 hardware thread N:1 Threading N application threads -> 1 hardware thread M:N Threading M application threads -> N hardware threads The same distinctions can be done at a multithreaded language or multithreading runtime level. 8 The problem How to schedule M tasks on N hardware threads? Latency vs 9 Throughput - Do we want to do all the work in a minimal amount of time? - Numerical computing - Machine learning - ... - Do we want to be fair? - Clients-server - Video decoding - ... Cooperative vs 10 Preemptive Cooperative multithreading: -
An Ideal Match?
24 November 2020 An ideal match? Investigating how well-suited Concurrent ML is to implementing Belief Propagation for Stereo Matching James Cooper [email protected] OutlineI 1 Stereo Matching Generic Stereo Matching Belief Propagation 2 Concurrent ML Overview Investigation of Alternatives Comparative Benchmarks 3 Concurrent ML and Belief Propagation 4 Conclusion Recapitulation Prognostication 5 References Outline 1 Stereo Matching Generic Stereo Matching Belief Propagation 2 Concurrent ML Overview Investigation of Alternatives Comparative Benchmarks 3 Concurrent ML and Belief Propagation 4 Conclusion Recapitulation Prognostication 5 References Outline 1 Stereo Matching Generic Stereo Matching Belief Propagation 2 Concurrent ML Overview Investigation of Alternatives Comparative Benchmarks 3 Concurrent ML and Belief Propagation 4 Conclusion Recapitulation Prognostication 5 References Stereo Matching Generally SM is finding correspondences between stereo images Images are of the same scene Captured simultaneously Correspondences (`disparity') are used to estimate depth SM is an ill-posed problem { can only make best guess Impossible to perform `perfectly' in general case Stereo Matching ExampleI (a) Left camera's image (b) Right camera's image Figure 1: The popular 'Tsukuba' example stereo matching images, so called because they were created by researchers at the University of Tsukuba, Japan. They are probably the most widely-used benchmark images in stereo matching. Stereo Matching ExampleII (a) Ground truth disparity map (b) Disparity map generated using a simple Belief Propagation Stereo Matching implementation Figure 2: The ground truth disparity map for the Tsukuba images, and an example of a possible real disparity map produced by using Belief Propagation Stereo Matching. The ground truth represents what would be expected if stereo matching could be carried out `perfectly'. -
Gnu Smalltalk Library Reference Version 3.2.5 24 November 2017
gnu Smalltalk Library Reference Version 3.2.5 24 November 2017 by Paolo Bonzini Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled \GNU Free Documentation License". 1 3 1 Base classes 1.1 Tree Classes documented in this manual are boldfaced. Autoload Object Behavior ClassDescription Class Metaclass BlockClosure Boolean False True CObject CAggregate CArray CPtr CString CCallable CCallbackDescriptor CFunctionDescriptor CCompound CStruct CUnion CScalar CChar CDouble CFloat CInt CLong CLongDouble CLongLong CShort CSmalltalk CUChar CByte CBoolean CUInt CULong CULongLong CUShort ContextPart 4 GNU Smalltalk Library Reference BlockContext MethodContext Continuation CType CPtrCType CArrayCType CScalarCType CStringCType Delay Directory DLD DumperProxy AlternativeObjectProxy NullProxy VersionableObjectProxy PluggableProxy SingletonProxy DynamicVariable Exception Error ArithmeticError ZeroDivide MessageNotUnderstood SystemExceptions.InvalidValue SystemExceptions.EmptyCollection SystemExceptions.InvalidArgument SystemExceptions.AlreadyDefined SystemExceptions.ArgumentOutOfRange SystemExceptions.IndexOutOfRange SystemExceptions.InvalidSize SystemExceptions.NotFound SystemExceptions.PackageNotAvailable SystemExceptions.InvalidProcessState SystemExceptions.InvalidState -
The Glib/GTK+ Development Platform
The GLib/GTK+ Development Platform A Getting Started Guide Version 0.8 Sébastien Wilmet March 29, 2019 Contents 1 Introduction 3 1.1 License . 3 1.2 Financial Support . 3 1.3 Todo List for this Book and a Quick 2019 Update . 4 1.4 What is GLib and GTK+? . 4 1.5 The GNOME Desktop . 5 1.6 Prerequisites . 6 1.7 Why and When Using the C Language? . 7 1.7.1 Separate the Backend from the Frontend . 7 1.7.2 Other Aspects to Keep in Mind . 8 1.8 Learning Path . 9 1.9 The Development Environment . 10 1.10 Acknowledgments . 10 I GLib, the Core Library 11 2 GLib, the Core Library 12 2.1 Basics . 13 2.1.1 Type Definitions . 13 2.1.2 Frequently Used Macros . 13 2.1.3 Debugging Macros . 14 2.1.4 Memory . 16 2.1.5 String Handling . 18 2.2 Data Structures . 20 2.2.1 Lists . 20 2.2.2 Trees . 24 2.2.3 Hash Tables . 29 2.3 The Main Event Loop . 31 2.4 Other Features . 33 II Object-Oriented Programming in C 35 3 Semi-Object-Oriented Programming in C 37 3.1 Header Example . 37 3.1.1 Project Namespace . 37 3.1.2 Class Namespace . 39 3.1.3 Lowercase, Uppercase or CamelCase? . 39 3.1.4 Include Guard . 39 3.1.5 C++ Support . 39 1 3.1.6 #include . 39 3.1.7 Type Definition . 40 3.1.8 Object Constructor . 40 3.1.9 Object Destructor . -
Tcl and Java Performance
Tcl and Java Performance http://ptolemy.eecs.berkeley.edu/~cxh/java/tclblend/scriptperf/scriptperf.html Tcl and Java Performance by H. John Reekie, University of California at Berkeley Christopher Hylands, University of California at Berkeley Edward A. Lee, University of California at Berkeley Abstract Combining scripting languages such as Tcl with lower−level programming languages such as Java offers new opportunities for flexible and rapid software development. In this paper, we benchmark various combinations of Tcl and Java against the two languages alone. We also provide some comparisons with JavaScript. Performance can vary by well over two orders of magnitude. We also uncovered some interesting threading issues that affect performance on the Solaris platform. "There are lies, damn lies and statistics" This paper is a work in progress, we used the information here to give our group some generalizations on the performance tradeoffs between various scripting languages. Updating the timing results to include JDK1.2 with a Just In Time (JIT) compiler would be useful. Introduction There is a growing trend towards integration of multiple languages through scripting. In a famously controversial white paper (Ousterhout 97), John Ousterhout, now of Scriptics Corporation, argues that scripting −− the use of a high−level, untyped, interpreted language to "glue" together components written in a lower−level language −− provides greater reuse benefits that other reuse technologies. Although traditionally a language such as C or C++ has been the lower−level language, more recent efforts have focused on using Java. Recently, Sun Microsystems laboratories announced two products aimed at fulfilling this goal with the Tcl and Java programming languages. -
GNU MP the GNU Multiple Precision Arithmetic Library Edition 6.2.1 14 November 2020
GNU MP The GNU Multiple Precision Arithmetic Library Edition 6.2.1 14 November 2020 by Torbj¨ornGranlund and the GMP development team This manual describes how to install and use the GNU multiple precision arithmetic library, version 6.2.1. Copyright 1991, 1993-2016, 2018-2020 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover Texts being \A GNU Manual", and with the Back-Cover Texts being \You have freedom to copy and modify this GNU Manual, like GNU software". A copy of the license is included in Appendix C [GNU Free Documentation License], page 132. i Table of Contents GNU MP Copying Conditions :::::::::::::::::::::::::::::::::::: 1 1 Introduction to GNU MP ::::::::::::::::::::::::::::::::::::: 2 1.1 How to use this Manual :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 2 2 Installing GMP ::::::::::::::::::::::::::::::::::::::::::::::::: 3 2.1 Build Options:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 3 2.2 ABI and ISA :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 8 2.3 Notes for Package Builds:::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 11 2.4 Notes for Particular Systems :::::::::::::::::::::::::::::::::::::::::::::::::::::: 12 2.5 Known Build Problems ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 14 2.6 Performance -
Development Environment for the Raspberry Pi Using a Cross Compiling Toolchain and Eclipse | Hertaville 07.10.13 13:37
Development Environment for the Raspberry Pi using a Cross Compiling Toolchain and Eclipse | Hertaville 07.10.13 13:37 Hertaville Welcome to Hertaville! Development Environment for the Raspberry Pi using a Cross Compiling Toolchain and Eclipse Posted on September 28, 2012 by halherta UPDATED July 15th 2013 In this blog entry the setup of a cross-compiling development environment for the Raspberry Pi will be demonstrated. This will include the Official Raspbian (armhf) cross compiling toolchain (available from github) Eclipse for C/C++ Developers (Linux) We will finally write a simple Hello World program on our development PC, compile it using the cross compiler and then deploy it onto our Raspberry Pi board to run it. I’m going to assume that you have already installed a Raspbian Wheezy image on your RPi board and that you have Linux installed on your desktop PC. For this tutorial I am using the Crunchbang 11 Linux OS (64-bit) on my PC. The instructions provided should work on most Debian/Ubuntu based Linux distributions running directly on a PC or as a a guest operating system via VMWare/ VirtualBox . A remote debugging tutorial; which I consider to be the continuation of this tutorial, can be found here. Finally, Derek Molloy has a great video tutorial on setting up a similar environment for the Beaglebone. Watching this video was incredibly informative and helped me set up this tutorial. So what is a cross compiling toolchain and why use one ? A native compiler such as the default gcc tool on the PC is a compiler that runs on an Intel machine, as well as creates binaries intended to be run on an Intel machine. -
Drawing in GTK+
CSci493.70 Graphical User Interface Programming Prof. Stewart Weiss Drawing in GTK+ Drawing in GTK+ Background In order to understand how to draw in GTK, you rst have to understand something about how GTK draws widgets, because how GTK draws widgets has an important role in how you design your drawing application. An understanding of how GTK draws widgets is also required if you ever plan to build your own custom widgets. Windows and Clipping Most windowing systems are designed around the idea that an application's visual display lies within a rectangular region on the screen called its window. The windowing system, e.g. Gnome or KDE or Explorer, does not automatically save the graphical content of an application's windows; instead it asks the application itself to repaint 1 its windows whenever it is needed. For example, if a window that is stacked below other windows gets raised to the top, then a client program has to repaint the area that was previously obscured. When the windowing system asks a client program to redraw part of a window, it sends an exposure event to the program that contains that window. An exposure event is simply an event sent from the underlying windowing system to a widget to notify it that it must redraw itself. In this context, a "window" means "a rectangular region with automatic clipping", not a top-level application window. Clipping is the act of removing portions of a window that do not need to be redrawn, or looked at the other way, it is determining which are the only regions of a window that must be redrawn. -
Gtk Marries Ada: the GUI Technology Revolution
GtkGtk MarriesMarries AdaAda:: TheThe GUIGUI TechnologyTechnology RevolutionRevolution [email protected] OverviewOverview History of GtkAda GtkAda Features Why Gtk Rather Than Other Toolkits? Why GtkAda rather than Gtk+? GtkAdaGtkAda -- HistoryHistory á The GIMP – GNU Photoshop clone á The Gtk+ library – Becomes independent á GtkGlade: a Gtk+ GUI builder á Gnome: a desktop manager á GVD: the GNU Visual Debugger GtkAdaGtkAda FeaturesFeatures ááHigh-level binding to the Gtk+ library – object-oriented – type safety – small and efficient ááHighly portable – Unixes: Linux, Solaris, … – Windows NT ááNative GtkAdaGtkAda FeaturesFeatures (2)(2) ááEvent handling ááDrawing services – Lines, rectangles, … – OpenGL (3D graphics) ááStyle support ááLarge set of widgets GtkAdaGtkAda -- WidgetWidget setset á Two types of widgets – containers and visual objects á About 100 widgets are provided á High-level widgets – notebook, text widget, tree, spin button, table, toolbar, ... GtkAdaGtkAda -- ScreenshotsScreenshots á Ctree GtkAdaGtkAda -- ScreenshotsScreenshots (2)(2) á OpenGL WhyWhy Gtk+?Gtk+? á Portable á Native á Extensible á Open Source á Actively developped á Thread-safe WhyWhy Gtk+?Gtk+? (2)(2) á High level widgets á Easy to use scrolling capabilities á Wide range of users á Very powerful layout capabilities – Complete set of containers á Powerful and easy to use GUI builder á Easy to bind TheThe GUIGUI BuilderBuilder ááMulti-language GUI builder – Language-independent save file (XML). – Code-generation specific to each language. – Dynamic loading -
Dynamic Object-Oriented Programming with Smalltalk
Dynamic Object-Oriented Programming with Smalltalk 1. Introduction Prof. O. Nierstrasz Autumn Semester 2009 LECTURE TITLE What is surprising about Smalltalk > Everything is an object > Everything happens by sending messages > All the source code is there all the time > You can't lose code > You can change everything > You can change things without restarting the system > The Debugger is your Friend © Oscar Nierstrasz 2 ST — Introduction Why Smalltalk? > Pure object-oriented language and environment — “Everything is an object” > Origin of many innovations in OO development — RDD, IDE, MVC, XUnit … > Improves on many of its successors — Fully interactive and dynamic © Oscar Nierstrasz 1.3 ST — Introduction What is Smalltalk? > Pure OO language — Single inheritance — Dynamically typed > Language and environment — Guiding principle: “Everything is an Object” — Class browser, debugger, inspector, … — Mature class library and tools > Virtual machine — Objects exist in a persistent image [+ changes] — Incremental compilation © Oscar Nierstrasz 1.4 ST — Introduction Smalltalk vs. C++ vs. Java Smalltalk C++ Java Object model Pure Hybrid Hybrid Garbage collection Automatic Manual Automatic Inheritance Single Multiple Single Types Dynamic Static Static Reflection Fully reflective Introspection Introspection Semaphores, Some libraries Monitors Concurrency Monitors Categories, Namespaces Packages Modules namespaces © Oscar Nierstrasz 1.5 ST — Introduction Smalltalk: a State of Mind > Small and uniform language — Syntax fits on one sheet of paper > -
Thread Scheduling in Multi-Core Operating Systems Redha Gouicem
Thread Scheduling in Multi-core Operating Systems Redha Gouicem To cite this version: Redha Gouicem. Thread Scheduling in Multi-core Operating Systems. Computer Science [cs]. Sor- bonne Université, 2020. English. tel-02977242 HAL Id: tel-02977242 https://hal.archives-ouvertes.fr/tel-02977242 Submitted on 24 Oct 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Ph.D thesis in Computer Science Thread Scheduling in Multi-core Operating Systems How to Understand, Improve and Fix your Scheduler Redha GOUICEM Sorbonne Université Laboratoire d’Informatique de Paris 6 Inria Whisper Team PH.D.DEFENSE: 23 October 2020, Paris, France JURYMEMBERS: Mr. Pascal Felber, Full Professor, Université de Neuchâtel Reviewer Mr. Vivien Quéma, Full Professor, Grenoble INP (ENSIMAG) Reviewer Mr. Rachid Guerraoui, Full Professor, École Polytechnique Fédérale de Lausanne Examiner Ms. Karine Heydemann, Associate Professor, Sorbonne Université Examiner Mr. Etienne Rivière, Full Professor, University of Louvain Examiner Mr. Gilles Muller, Senior Research Scientist, Inria Advisor Mr. Julien Sopena, Associate Professor, Sorbonne Université Advisor ABSTRACT In this thesis, we address the problem of schedulers for multi-core architectures from several perspectives: design (simplicity and correct- ness), performance improvement and the development of application- specific schedulers.