Page type: project

Cornell Active Messages;Cornell Active Messages;Cornell Active Messages Implementations;Active Messages for U-Net;A source-code release of U-Net Active Messages is part of the;general U-Net release. It conforms to the GAM-1.1 spec below. For more;information, see the U-Net project pages.;Active Messages for the IBM SP-2 An object-code;release of SP2 AM for AIX 3.2 is available in gam-1.0.aix3.tar.Z. It conforms to the;GAM-1.1 spec below. Please read README and INSTALL files in the distribution for instructions;on using SP2 AM. For more information contact: Chi-Chao Chang, Grzegorz Czajkowski, Thorsten von Eicken.;Please read the ReleaseNotes.aix3 file;to find out about the changes from the previous version. The current;version of SP2 AM is 1.0f.;Also, there is a release for AIX 4.1.: gam-1.0.aix4.tar.Z. The major difference;between the AIX 4.1 release to the 3.2 is a modified;/usr/lpp/ppe.poe/lib/us/libmpci.a, which is included in the;distribution. Please read the documentation in the package for;details.;We are interested in knowing who is currently using SP2 AM. Please;click here to send a brief;note letting us know something about you, your organization, and the;uses you intend for SP2 AM.;Selected Publications on Active Messages;Low-Latency Communication on the IBM;RISC System/6000 SP Chi-Chao Chang, Grzegorz Czajkowski,;Chris Hawblitzel, and Thorsten von Eicken, to appear in ACM/IEEE;Supercomputing '96, Pittsburgh, PA, November 1996.;Abstract:;The IBM SP is one of the most powerful commercial MPPs, yet, in spite;of its fast processors and high network bandwidth, the SP's;communication latency is inferior to older machines such as the TMC;CM-5 or Meiko CS-2. This paper investigates the use of Active Messages;(AM) communication primitives as an alternative to the standard;message passing in order to reduce communication overheads and to;offer a good building block for higher layers of software.;The first part of this paper describes an implementation of Active;Messages (SP AM) which is layered directly on top of the SP's network;adapter (TB2). With comparable bandwidth, SP AM's low overhead yields;a round-trip latency that is 40% lower than IBM MPL's. The second;part of the paper demonstrates the power of AM as a communication;substrate by layering Split-C as well as MPI over it. Split-C;benchmarks are used to compare the SP to other MPPs and show that low;message overhead and high throughput compensate for SP's high network;latency. The MPI implementation is based on the freely available;MPICH version and achieves performance equivalent to IBM's MPI-F on;the NAS benchmarks.;Design and Performance of Active Messages on the;SP-2;Chi-Chao Chang, Grzegorz Czajkowski, and Thorsten von Eicken,;Cornell CS Technical Report 96-1572, February 1996.;Abstract:;This technical report describes the design, implementation, and;evaluation of Active Messages on the IBM SP-2. The implementation;benchmarked here uses the standard TB2 network adapter firmware but;does not use any IBM software on the Power2 processor. We assume;familiarity with the concepts underlying Active Messages. The main;performance characteristics are a one-word message round-trip time;of 51.0 us and an asymptotic network bandwidth of 34.3 MB/s.;After presenting selected implementation details, the paper focuses;on detailed performance analysis, including a comparison with IBM's;Message Passing Layer (MPL) and Split-C benchmarks.;Generic Active Message Specification, Version 1.1.;The Generic Active Message Specification, Version 1.1 defines an Active;Messages interface which is portable across a variety of parallel machines.;Implementations are available for the;U-Net ATM cluster,;the;Meiko CS-2,;the;HPAM FDDI ring,;the;Paragon,;and the;SP-2.;Low-Latency Communication over ATM Networks;using Active Messages.;Thorsten von Eicken, Veena Avula, Anyndia Basu, Vineet Buch,;Presented at Hot Interconnects II,;Aug 1994, Palo Alto, CA.;An abridged version of this paper appears in IEEE Micro Magazine, Feb. 1995.;Slides from Hot Interconnect talk.;Abstract:;Recent developments in communication architectures for;parallel machines have made significant progress and reduced the;communication overheads and latencies by over an order of magnitude as;compared to earlier proposals. This paper examines whether these;techniques can carry over to clusters of workstations connected by an;ATM network even though clusters use standard operating system;software, are equipped with network interfaces optimized for stream;communication, do not allow direct protected user-level access to the;network, and use networks without reliable transmission or flow;control.;In a first part, this paper describes the differences in;communication characteristics between clusters of workstations built;from standard hardware and software components and state-of-the-art;multiprocessors. The lack of flow control and of operating system;coordination affects the communication layer design significantly and;requires larger buffers at each end than on multiprocessors. A second;part evaluates a prototype implementation of the low-latency Active;Messages communication model on a Sun workstation cluster;interconnected by an ATM network. Measurements show;application-to-application latencies of about 20 microseconds for small;messages which is roughly comparable to the Active Messages;implementation on the Thinking Machines CM-5 multiprocessor.;Active Messages: a Mechanism for Integrated Communication and;Computation.;von Eicken, T., D. E. Culler, S. C. Goldstein, and K. E. Schauser,;Proceedings of the 19th Int'l Symp. on Computer Architecture,;May 1992, Gold Coast, Australia.;Abstract;The design challenge for large-scale multiprocessors is (1) to;minimize communication overhead, (2) allow communication to overlap;computation, and (3) coordinate the two without sacrificing;processor cost/performance. We show that existing message passing;multiprocessors have unnecessarily high communication costs. Research;prototypes of message driven machines demonstrate low communication;overhead, but poor processor cost/performance. We introduce a simple;communication mechanism, Active Messages, show that it is;intrinsic to both architectures, allows cost effective use of the;hardware, and offers tremendous flexibility. Implementations on nCUBE/2;And CM-5 are described and evaluated using a split-phase shared-memory;extension to C, Split-C. We further show that active messages;are sufficient to implement the dynamically scheduled languages for;which message driven machines were designed. With this mechanism,;latency tolerance becomes a programming/compiling concern. Hardware;support for active messages is desirable and we outline a range of;enhancements to mainstream processors.;Active Messages: an Efficient;Communication Architecture for Multiprocessors. von Eicken, T.,;Ph.D. Thesis, November 1993, University of California at Berkeley.;Projects at other sites;Active Messages;in the Berkeley NoW project;For further information contact;Thorsten von Eicken;