The impact of taskyield on the design of tasks communicating through MPI

Joseph Schuchart; Keisuke Tsugane; José Gracia; Mitsuhisa Sato

doi:10.1007/978-3-319-98521-3_1

The impact of taskyield on the design of tasks communicating through MPI

Joseph Schuchart
, Keisuke Tsugane
, José Gracia
, Mitsuhisa Sato

Institute for Advanced Computational Science

University of Tsukuba
University of Stuttgart

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

18 Scopus citations

Abstract

The OpenMP tasking directives promise to help expose a higher degree of concurrency to the runtime than traditional worksharing constructs, which is especially useful for irregular applications. In combination with process-based parallelization such as MPI, the taskyield construct in OpenMP can become a crucial aspect as it helps to hide communication latencies by allowing a thread to execute other tasks while completion of the communication operation is pending. Unfortunately, the OpenMP standard only provides little guarantees on the characteristics of the taskyield operation. In this paper, we explore different potential implementations of taskyield and present a portable black-box tool for detecting the actual implementation used in existing OpenMP compilers/runtimes. Furthermore, we discuss the impact of the different taskyield implementations on the task design of the communication-heavy Blocked Cholesky Factorization and the difference in performance that can be observed, which we found to be over 20 %.

Original language	English
Title of host publication	Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings
Editors	Pedro Valero-Lara, Sergi Mateo Bellido, Xavier Martorell, Jesus Labarta, Bronis R. de Supinski
Publisher	Springer Verlag
Pages	3-17
Number of pages	15
ISBN (Print)	9783319985206
DOIs	https://doi.org/10.1007/978-3-319-98521-3_1
State	Published - 2018
Event	14th International Workshop on OpenMP, IWOMP 2018 - Barcelona, Spain Duration: Sep 26 2018 → Sep 28 2018

Publication series

Name	Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume	11128 LNCS
ISSN (Print)	0302-9743
ISSN (Electronic)	1611-3349

Conference

Conference	14th International Workshop on OpenMP, IWOMP 2018
Country/Territory	Spain
City	Barcelona
Period	09/26/18 → 09/28/18

Keywords

Blocked Cholesky Factorization
Hybrid MPI/OpenMP
OmpSs
OpenMP tasks
Task-yield

Access to Document

10.1007/978-3-319-98521-3_1

Cite this

Schuchart, J., Tsugane, K., Gracia, J., & Sato, M. (2018). The impact of taskyield on the design of tasks communicating through MPI. In P. Valero-Lara, S. M. Bellido, X. Martorell, J. Labarta, & B. R. de Supinski (Eds.), Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings (pp. 3-17). (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 11128 LNCS). Springer Verlag. https://doi.org/10.1007/978-3-319-98521-3_1

Schuchart, Joseph ; Tsugane, Keisuke ; Gracia, José et al. / The impact of taskyield on the design of tasks communicating through MPI. Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings. editor / Pedro Valero-Lara ; Sergi Mateo Bellido ; Xavier Martorell ; Jesus Labarta ; Bronis R. de Supinski. Springer Verlag, 2018. pp. 3-17 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)).

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abstract = "The OpenMP tasking directives promise to help expose a higher degree of concurrency to the runtime than traditional worksharing constructs, which is especially useful for irregular applications. In combination with process-based parallelization such as MPI, the taskyield construct in OpenMP can become a crucial aspect as it helps to hide communication latencies by allowing a thread to execute other tasks while completion of the communication operation is pending. Unfortunately, the OpenMP standard only provides little guarantees on the characteristics of the taskyield operation. In this paper, we explore different potential implementations of taskyield and present a portable black-box tool for detecting the actual implementation used in existing OpenMP compilers/runtimes. Furthermore, we discuss the impact of the different taskyield implementations on the task design of the communication-heavy Blocked Cholesky Factorization and the difference in performance that can be observed, which we found to be over 20 \%.",

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author = "Joseph Schuchart and Keisuke Tsugane and Jos{\'e} Gracia and Mitsuhisa Sato",

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Schuchart, J, Tsugane, K, Gracia, J & Sato, M 2018, The impact of taskyield on the design of tasks communicating through MPI. in P Valero-Lara, SM Bellido, X Martorell, J Labarta & BR de Supinski (eds), Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings. Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), vol. 11128 LNCS, Springer Verlag, pp. 3-17, 14th International Workshop on OpenMP, IWOMP 2018, Barcelona, Spain, 09/26/18. https://doi.org/10.1007/978-3-319-98521-3_1

The impact of taskyield on the design of tasks communicating through MPI. / Schuchart, Joseph; Tsugane, Keisuke; Gracia, José et al.
Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings. ed. / Pedro Valero-Lara; Sergi Mateo Bellido; Xavier Martorell; Jesus Labarta; Bronis R. de Supinski. Springer Verlag, 2018. p. 3-17 (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics); Vol. 11128 LNCS).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - The impact of taskyield on the design of tasks communicating through MPI

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AU - Tsugane, Keisuke

AU - Gracia, José

AU - Sato, Mitsuhisa

N1 - Publisher Copyright: © Springer Nature Switzerland AG 2018.

PY - 2018

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N2 - The OpenMP tasking directives promise to help expose a higher degree of concurrency to the runtime than traditional worksharing constructs, which is especially useful for irregular applications. In combination with process-based parallelization such as MPI, the taskyield construct in OpenMP can become a crucial aspect as it helps to hide communication latencies by allowing a thread to execute other tasks while completion of the communication operation is pending. Unfortunately, the OpenMP standard only provides little guarantees on the characteristics of the taskyield operation. In this paper, we explore different potential implementations of taskyield and present a portable black-box tool for detecting the actual implementation used in existing OpenMP compilers/runtimes. Furthermore, we discuss the impact of the different taskyield implementations on the task design of the communication-heavy Blocked Cholesky Factorization and the difference in performance that can be observed, which we found to be over 20 %.

AB - The OpenMP tasking directives promise to help expose a higher degree of concurrency to the runtime than traditional worksharing constructs, which is especially useful for irregular applications. In combination with process-based parallelization such as MPI, the taskyield construct in OpenMP can become a crucial aspect as it helps to hide communication latencies by allowing a thread to execute other tasks while completion of the communication operation is pending. Unfortunately, the OpenMP standard only provides little guarantees on the characteristics of the taskyield operation. In this paper, we explore different potential implementations of taskyield and present a portable black-box tool for detecting the actual implementation used in existing OpenMP compilers/runtimes. Furthermore, we discuss the impact of the different taskyield implementations on the task design of the communication-heavy Blocked Cholesky Factorization and the difference in performance that can be observed, which we found to be over 20 %.

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T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

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A2 - Bellido, Sergi Mateo

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A2 - Labarta, Jesus

A2 - de Supinski, Bronis R.

PB - Springer Verlag

T2 - 14th International Workshop on OpenMP, IWOMP 2018

Y2 - 26 September 2018 through 28 September 2018

ER -

Schuchart J, Tsugane K, Gracia J, Sato M. The impact of taskyield on the design of tasks communicating through MPI. In Valero-Lara P, Bellido SM, Martorell X, Labarta J, de Supinski BR, editors, Evolving OpenMP for Evolving Architectures - 14th International Workshop on OpenMP, IWOMP 2018, Proceedings. Springer Verlag. 2018. p. 3-17. (Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)). doi: 10.1007/978-3-319-98521-3_1

The impact of taskyield on the design of tasks communicating through MPI

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