Multitasking 3-D forward modeling using high-order finite difference methods on the Cray X-MP/416

Journal Article · Fri Jan 01 04:00:00 EST 1988 · Int. J. Supercomput. Appl.; (United States)

DOI:https://doi.org/10.1177/109434208800200104· OSTI ID:6930276

Terki-Hassaine, O; Leiss, E L

The CRAY X-MP/416 was used to multitask 3-D forward modeling by the high-order finite difference method. Flowtrace analysis reveals that the most expensive operation in the unitasked program is a matrix vector multiplication. The in-core and out-of-core versions of a reentrant subroutine can perform any fraction of the matrix vector multiplication independently, a pattern compatible with multitasking. The matrix vector multiplication routine can be distributed over two to four processors. The rest of the program utilizes the microtasking feature that lets the system treat independent iterations of DO-loops as subtasks to be performed by any available processor. The availability of the Solid-State Storage Device (SSD) meant the I/O wait time was virtually zero. A performance study determined a theoretical speedup, taking into account the multitasking overhead. Multitasking programs utilizing both macrotasking and microtasking features obtained actual speedups that were approximately 80% of the ideal speedup.

• Research Organization: Univ. of Houston, Houston, TX (US)
• OSTI ID: 6930276
• Journal Information: Int. J. Supercomput. Appl.; (United States), Journal Name: Int. J. Supercomput. Appl.; (United States) Vol. 2:1; ISSN IJSAE
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
990210* -- Supercomputers-- (1987-1989)
COMPUTER CALCULATIONS
COMPUTERS
CRAY COMPUTERS
FINITE DIFFERENCE METHOD
ITERATIVE METHODS
MATRICES
NUMERICAL SOLUTION
PERFORMANCE