NESC9636 CUBESIM.

1. NAME OR DESIGNATION OF PROGRAM:  CUBESIM.

3. DESCRIPTION OF PROGRAM OR FUNCTION

CUBESIM is a set of subroutine  libraries and programs for the simulation of message-passing parallel computers and shared-memory parallel computers. Subroutines are supplied to simulate the Intel hypercube and the Denelcor HEP parallel computers. The system permits a user to develop and test parallel programs written in C or FORTRAN on a single processor. The user may alter such hypercube parameters as message startup times, packet size, and the computation-to-communication ratio. The simulation generates a trace file that can be used for debugging, performance analysis, or graphical display.

4. METHOD OF SOLUTION

The CUBESIM simulator is linked with the user's parallel application routines to run as a single UNIX process. The simulator library provides a small operating system to perform process and message management.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Up to 128 processors can be simulated with a virtual memory limit of 6 million bytes. Up  to 1000 processes can be simulated.

6. TYPICAL RUNNING TIME

Run times are a function of the user's application. In non-aspp (assembler post processor) mode, the simulation runs at approximately the speed of the VAX. In aspp mode, the simulation is, in effect, interpreted and slowed by a factor of  20 in order to gather the detailed performance information. Therefore, simulations can run in less than a second or large applications can take several days.

7. UNUSUAL FEATURES OF THE PROGRAM

Besides simulation of message- passing parallel processors, the simulator contains subroutines to simulate the Denelcor HEP shared-memory multiprocessor and more general routines to support shared-memory lock and event variables.

8. RELATED AND AUXILIARY PROGRAMS

Three postprocessors, ccplot, nstats, and tracel, are included to process the trace file produced  by a simulation and provide tabular and graphical output of CPU utilization and message-passing statistics. A portable, but less powerful, version of the simulator, mpsim, is also included. This simulator uses the UNIX forks and pipes services to implement message passing and should run on most UNIX systems.It was tested on UNIX 4.2, XENIX, Sequent UNIX, Ultrix, and Encore UNIX systems.
    CUBESIM is based on the MULTITASKER (NESC 9684) program.

10. REFERENCES

- Eugene D. Brooks
A Multitasking Kernel for the C and Fortran Programming Languages,    UCID-20167, September 1984.
- iPSC, User's Guide, Intel 17455-03, October 1985.

- T.H. Dunigan:
  A Message-Passing Multiprocessor Simulator
  ORNL/TM-9966  (May 1986)

11. MACHINE REQUIREMENTS

Virtual memory requirements are a function of the user's problem size. Approximately 2.5 million bytes of disk space is required to load the contents of the transmittal tape. The  minimum disk requirement is approximately 500,000 bytes.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  Berkeley UNIX 4.2 or DEC Ultrix.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The use of FORTRAN COMMON and C external variables is restricted.

15. NAME AND ESTABLISHMENT OF AUTHORS

          T.H. Dunigan
          Engineering Physics and Mathematics Division
          Oak Ridge National Laboratory

File name	File description	Records
NESC9636_01.001	Information file	33
NESC9636_01.002	CUBESIM source,... in UNIX TAR format	208