Using Coarrays to Parallelize Legacy Fortran Applications: Strategy and Case Study
Joint Authors
Morris, Karla
Radhakrishnan, Hari
Rouson, Damian W. I.
Shende, Sameer
Kassinos, Stavros C.
Source
Issue
Vol. 2015, Issue 2015 (31 Dec. 2015), pp.1-12, 12 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2015-05-28
Country of Publication
Egypt
No. of Pages
12
Main Subjects
Abstract EN
This paper summarizes a strategy for parallelizing a legacy Fortran 77 program using the object-oriented (OO) and coarray features that entered Fortran in the 2003 and 2008 standards, respectively.
OO programming (OOP) facilitates the construction of an extensible suite of model-verification and performance tests that drive the development.
Coarray parallel programming facilitates a rapid evolution from a serial application to a parallel application capable of running on multicore processors and many-core accelerators in shared and distributed memory.
We delineate 17 code modernization steps used to refactor and parallelize the program and study the resulting performance.
Our initial studies were done using the Intel Fortran compiler on a 32-core shared memory server.
Scaling behavior was very poor, and profile analysis using TAU showed that the bottleneck in the performance was due to our implementation of a collective, sequential summation procedure.
We were able to improve the scalability and achieve nearly linear speedup by replacing the sequential summation with a parallel, binary tree algorithm.
We also tested the Cray compiler, which provides its own collective summation procedure.
Intel provides no collective reductions.
With Cray, the program shows linear speedup even in distributed-memory execution.
We anticipate similar results with other compilers once they support the new collective procedures proposed for Fortran 2015.
American Psychological Association (APA)
Radhakrishnan, Hari& Rouson, Damian W. I.& Morris, Karla& Shende, Sameer& Kassinos, Stavros C.. 2015. Using Coarrays to Parallelize Legacy Fortran Applications: Strategy and Case Study. Scientific Programming،Vol. 2015, no. 2015, pp.1-12.
https://search.emarefa.net/detail/BIM-1076555
Modern Language Association (MLA)
Radhakrishnan, Hari…[et al.]. Using Coarrays to Parallelize Legacy Fortran Applications: Strategy and Case Study. Scientific Programming No. 2015 (2015), pp.1-12.
https://search.emarefa.net/detail/BIM-1076555
American Medical Association (AMA)
Radhakrishnan, Hari& Rouson, Damian W. I.& Morris, Karla& Shende, Sameer& Kassinos, Stavros C.. Using Coarrays to Parallelize Legacy Fortran Applications: Strategy and Case Study. Scientific Programming. 2015. Vol. 2015, no. 2015, pp.1-12.
https://search.emarefa.net/detail/BIM-1076555
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1076555