Active Messages

Updated Active Messages Interface Specification as of 9/28/1996.

This interface generalizes previous active messages interfaces to support a broader spectrum of applications such as client/server programs, file systems, operating systems, as well continuing support for parallel programs.

With recent advances in local area networks, networks of workstations differ from massively parallel processors primarily in packaging, cost and software emphasis. The key open architectural question is the nature of the network interface or the communication architecture: its hardware organization and logical abstraction as a basis for communication.

Active Messages represent a RISC approach to communication, providing simple primitives, rather than solutions, which expose the full hardware performance to higher layers. Active Messages are intended to serve as a substrate for building libraries that provide higher-level communication abstractions and for generating communication code from a parallel-language compiler, rather than for direct use by programmers. It is currently in use at UC Berkeley by the Fast Communication layers (sockets, RPC and MPI), the xFS parallel file system, the Split-C and Id compilers, as well as in other libraries like Scalapack.

This project investigates Active Messages on a broad range of hardware, including a dedicated message processor per node (Intel Paragon and Myrinet) an FDDI interface at the graphics bus of a high end workstation (HP 735 with Medusa), and a conventional interface to the next generation LAN (Sparc 10 with Sahi-1 ATM). We will thus demonstrate concepts by construction and evaluate them on real programs on real machines. The result will be a clearer understanding of the communication architecture and trade-offs in the hardware organization of the network interface.

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Software Releases

Lanai Active Messages
GAM Microbenchmarks


Professors Students
  • Brent Chun
  • Cedric Krumbein
  • Alan Mainwaring
  • Rich Martin
  • Chad Yoshikawa