Concurrency and Computation: Practice & Experience

Mascarenhas, Edward; Rego, Vernon

doi: 10.1002/(SICI)1096-9128(19980810)10:9<673::AID-CPE362>3.0.CO;2-5pmid: N/A

We present a novel and portable threads‐based system for concurrent applications on shared‐ and distributed‐memory environments. The Ariadne system provides stateful user‐space threads that can be very effective in medium to coarse grained applications. The interface is the same for uniprocessors and multiprocessors. Sequential programs are readily converted into parallel programs for shared or distributed memory, with low development effort. Ariadne supports the development of customized schedulers, and offers a thread migration capability in distributed environments. Scheduling of computations at the threads level enables both task‐ and data‐driven executions. Thread migration is a useful feature which turns remote memory accesses into local accesses, enables load‐balancing and simplifies program development. Ariadne employs a unique runtime stack rewriting mechanism to migrate threads between homogeneous processors. Ariadne currently runs on the SPARC (SunOS 4.x, SunOS 5.x), Sequent Symmetry, Intel Paragon, Silicon Graphics IRIX and IBM RS/6000 environments. We present some examples of Ariadne programs, along with performance measurements. © 1998 John Wiley & Sons, Ltd.

Gu, Weiming; Eisenhauer, Greg; Schwan, Karsten; Vetter, Jeffrey

doi: 10.1002/(SICI)1096-9128(19980810)10:9<699::AID-CPE367>3.0.CO;2-7pmid: N/A

Advances in high performance computing, communications and user interfaces enable developers to construct increasingly interactive high performance applications. The Falcon system presented in this paper supports such interactivity by providing runtime libraries, tools and user interfaces that permit the on‐line monitoring and steering of large‐scale parallel codes. The principal aspects of Falcon described in this paper are its abstractions and tools for capture and analysis of application‐specific program information, performed on‐line, with controlled latencies and scalable to parallel machines of substantial size. In addition, Falcon provides support for the on‐line graphical display of monitoring information, and it allows programs to be steered during their execution, by human users or algorithmically. This paper presents our basic research motivation, outlines the Falcon system's functionality, and includes a detailed evaluation of its performance characteristics in light of its principal contributions. Falcon's functionality and performance evaluation are driven by our experiences with large‐scale parallel applications being developed with end users in physics and in atmospheric sciences. The sample application highlighted in this paper is a molecular dynamics simulation program (MD) used by physicists to study the statistical mechanics of liquids. © 1998 John Wiley & Sons, Ltd.