ReLooper: Refactoring for Loop Parallelism

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An Eclipse-based refactoring tool that performs tasks automatically.

In the multicore era, sequential programs need to be refactored for parallelism. The next version of Java provides ParallelArray, an array data structure that supports parallel operations over the array elements. For example, one can "apply" a procedure to each element, or "reduce" all elements to a new element in parallel.

Refactoring an array to a ParallelArray requires: (a) analyzing whether the loop iterations are safe for parallel execution, and (b) replacing loops with the equivalent parallel operations. When done manually, these tasks are non-trivial and time-consuming.

In this presentation, Danny Dig presents ReLooper, an Eclipse-based refactoring tool, that performs these tasks automatically. Experience with refactoring real programs shows that ReLooper is useful: it reduces the burden of analyzing and rewriting parallel loops, and it is fast enough to be used interactively.

This session, entitled "ReLooper: Refactoring for Loop Parallelism," will be presented via live stream at http://media.cs.uiuc.edu/live/upcrc0910/upcrc1015thx1138.asx on Thursday, October 15, 2009 at 4:00 PM (Central Time).

Danny Dig is a PI at the University of Illinois at Urbana-Champaign, where he leads research on refactorings for parallelism. He got a PhD from Illinois, working on upgrading applications to use the newer APIs of software libraries. Before coming to Illinois he built JavaRefactor, the first open-source refactoring engine for Java.

Real World Parallelism Webinar Series
  • November 17, 2009
    Visual Effects for Animation - presented by DreamWorks Animation
    Speaker: Ron Henderson (Bio)

    Ron Henderson manages the FX Tools group at DreamWorks Animation, where he is responsible for developing physical simulation and procedural modeling tools. These systems have been used for key visual effects in recent films such as Kung Fu Panda and Monsters vs. Aliens (March 2009).

    Prior to joining DreamWorks in 2002 he was a senior scientist at Caltech with a joint appointment to the Applied Math and Aeronautics departments, where he worked on efficient techniques for the direct numerical simulation of fluid turbulence.

    Abstract:
    In this webinar, Ron Henderson will show examples of visual effects, from hair and feathers to smoke and fire, from a variety of DreamWorks Animation feature films. He will discuss in general terms the kinds of techniques used to achieve particular visual effects. Finally, Henderson will show a detailed breakdown of the dam-breaking scene from Madagascar: Escape 2 Africa, demonstrating how different elements of key frame animation, simulation, and rendering are combined in a real production shot.

  • December 1, 2009
    A Quick and Easy Way to Parallelize a Legacy Codebase with Intel® Threading Building Blocks (TBBs)
    Speaker: Bernard Laberge, Avid, Senior Principal Engineer (Bio)

    Bernard Laberge is a senior principal engineer in the video editors division at Avid. During his seven years with the company he has been actively involved in the replacement of the legacy video processing engines used by Avid editors with a common hardware-abstracted, component-based video processing engine currently running on the CPU with SIMD optimized code, GPU, and dedicated hardware.

    Abstract:
    Learn how to overcome the limitations of a thread-based scheduler, including dealing with the absence of recursive parallelism support and the inefficient handling of unbalanced processing load. Bernard Laberge addresses how Avid resolved the expensive refactoring of their thread-based scheduler into a task-based solution by choosing Intel® Threading Building Blocks (TBBs). He explores how Avid was able to easily integrate the Intel TBBs into their video editor applications and more than 5 million lines of code.

  • December 15, 2009
    How to Use Intel® Parallel Studio to Streamline Code Development in a Multicore Environment
    Speaker: Matt Dunbar, Director for Performance Technology, SIMULIA (Bio)

    Matt Dunbar is the director for performance technology at SIMULIA. Since joining the company in 1993, he has worked on parallelization of the Abaqus suite of products, initially for shared memory architectures and more recently for distributed memory architectures. Dunbar has also been intimately involved in selecting both the hardware and software tools used in the development of the Abaqus product line.

    Abstract:
    Resolve elusive, costly multithreading errors quickly and efficiently with Intel® Parallel Studio. While many coding problems that lead to bugs in software applications are typically straightforward logic errors, errors in managing memory and in multithreading code can sometimes take weeks to months to diagnose and fix. Matt Dunbar explores how and why taking advantage of multicore processors through multithreaded code is critical for compute-intensive applications. While spotlighting his work on SIMULIA's Abaqus finite element solver, Dunbar addresses the need for multicore execution and shares his experiences using Intel Parallel Studio to streamline code development in a multicore environment.