Reconfigurable Out-of-Order System for Fluid Dynamics Computation Using Unstructured Mesh

Takayuki AKAMINE; Mohamad Sofian ABU TALIP; Yasunori OSANA; Naoyuki FUJITA; Hideharu AMANO

doi:10.1587/transinf.E97.D.1225

Reconfigurable Out-of-Order System for Fluid Dynamics Computation Using Unstructured Mesh

Takayuki AKAMINE, Mohamad Sofian ABU TALIP, Yasunori OSANA, Naoyuki FUJITA, Hideharu AMANO

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Computational fluid dynamics (CFD) is an important tool for designing aircraft components. FaSTAR (Fast Aerodynamics Routines) is one of the most recent CFD packages and has various subroutines. However, its irregular and complicated data structure makes it difficult to execute FaSTAR on parallel machines due to memory access problem. The use of a reconfigurable platform based on field programmable gate arrays (FPGAs) is a promising approach to accelerating memory-bottlenecked applications like FaSTAR. However, even with hardware execution, a large number of pipeline stalls can occur due to read-after-write (RAW) data hazards. Moreover, it is difficult to predict when such stalls will occur because of the unstructured mesh used in FaSTAR. To eliminate this problem, we developed an out-of-order mechanism for permuting the data order so as to prevent RAW hazards. It uses an execution monitor and a wait buffer. The former identifies the state of the computation units, and the latter temporarily stores data to be processed in the computation units. This out-of-order mechanism can be applied to various types of computations with data dependency by changing the number of execution monitors and wait buffers in accordance with the equations used in the target computation. An out-of-order system can be reconfigured by automatic changing of the parameters. Application of the proposed mechanism to five subroutines in FaSTAR showed that its use reduces the number of stalls to less than 1% compared to without the mechanism. In-order execution was speeded up 2.6-fold and software execution was speeded up 2.9-fold using an Intel Core 2 Duo processor with a reasonable amount of overhead.

Publication: IEICE TRANSACTIONS on Information Vol.E97-D No.5 pp.1225-1234

Publication Date: 2014/05/01

Publicized

Online ISSN: 1745-1361

DOI: 10.1587/transinf.E97.D.1225

Type of Manuscript: PAPER

Category: Computer System

Authors

Takayuki AKAMINE
  Keio University
Mohamad Sofian ABU TALIP
  Keio University
Yasunori OSANA
  University of the Ryukyus
Naoyuki FUJITA
  Japan Aerospace Exploration Agency (JAXA)
Hideharu AMANO
  Keio University

Keyword

computational fluid dynamics (CFD), field programmable gate array (FPGA), scientific computations, reconfigurable hardware, out-of-order system

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Takayuki AKAMINE, Mohamad Sofian ABU TALIP, Yasunori OSANA, Naoyuki FUJITA, Hideharu AMANO, "Reconfigurable Out-of-Order System for Fluid Dynamics Computation Using Unstructured Mesh" in IEICE TRANSACTIONS on Information, vol. E97-D, no. 5, pp. 1225-1234, May 2014, doi: 10.1587/transinf.E97.D.1225.
Abstract: Computational fluid dynamics (CFD) is an important tool for designing aircraft components. FaSTAR (Fast Aerodynamics Routines) is one of the most recent CFD packages and has various subroutines. However, its irregular and complicated data structure makes it difficult to execute FaSTAR on parallel machines due to memory access problem. The use of a reconfigurable platform based on field programmable gate arrays (FPGAs) is a promising approach to accelerating memory-bottlenecked applications like FaSTAR. However, even with hardware execution, a large number of pipeline stalls can occur due to read-after-write (RAW) data hazards. Moreover, it is difficult to predict when such stalls will occur because of the unstructured mesh used in FaSTAR. To eliminate this problem, we developed an out-of-order mechanism for permuting the data order so as to prevent RAW hazards. It uses an execution monitor and a wait buffer. The former identifies the state of the computation units, and the latter temporarily stores data to be processed in the computation units. This out-of-order mechanism can be applied to various types of computations with data dependency by changing the number of execution monitors and wait buffers in accordance with the equations used in the target computation. An out-of-order system can be reconfigured by automatic changing of the parameters. Application of the proposed mechanism to five subroutines in FaSTAR showed that its use reduces the number of stalls to less than 1% compared to without the mechanism. In-order execution was speeded up 2.6-fold and software execution was speeded up 2.9-fold using an Intel Core 2 Duo processor with a reasonable amount of overhead.
URL: https://globals.ieice.org/en_transactions/information/10.1587/transinf.E97.D.1225/_p

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@ARTICLE{e97-d_5_1225,
author={Takayuki AKAMINE, Mohamad Sofian ABU TALIP, Yasunori OSANA, Naoyuki FUJITA, Hideharu AMANO, },
journal={IEICE TRANSACTIONS on Information},
title={Reconfigurable Out-of-Order System for Fluid Dynamics Computation Using Unstructured Mesh},
year={2014},
volume={E97-D},
number={5},
pages={1225-1234},
abstract={Computational fluid dynamics (CFD) is an important tool for designing aircraft components. FaSTAR (Fast Aerodynamics Routines) is one of the most recent CFD packages and has various subroutines. However, its irregular and complicated data structure makes it difficult to execute FaSTAR on parallel machines due to memory access problem. The use of a reconfigurable platform based on field programmable gate arrays (FPGAs) is a promising approach to accelerating memory-bottlenecked applications like FaSTAR. However, even with hardware execution, a large number of pipeline stalls can occur due to read-after-write (RAW) data hazards. Moreover, it is difficult to predict when such stalls will occur because of the unstructured mesh used in FaSTAR. To eliminate this problem, we developed an out-of-order mechanism for permuting the data order so as to prevent RAW hazards. It uses an execution monitor and a wait buffer. The former identifies the state of the computation units, and the latter temporarily stores data to be processed in the computation units. This out-of-order mechanism can be applied to various types of computations with data dependency by changing the number of execution monitors and wait buffers in accordance with the equations used in the target computation. An out-of-order system can be reconfigured by automatic changing of the parameters. Application of the proposed mechanism to five subroutines in FaSTAR showed that its use reduces the number of stalls to less than 1% compared to without the mechanism. In-order execution was speeded up 2.6-fold and software execution was speeded up 2.9-fold using an Intel Core 2 Duo processor with a reasonable amount of overhead.},
keywords={},
doi={10.1587/transinf.E97.D.1225},
ISSN={1745-1361},
month={May},}

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TY - JOUR
TI - Reconfigurable Out-of-Order System for Fluid Dynamics Computation Using Unstructured Mesh
T2 - IEICE TRANSACTIONS on Information
SP - 1225
EP - 1234
AU - Takayuki AKAMINE
AU - Mohamad Sofian ABU TALIP
AU - Yasunori OSANA
AU - Naoyuki FUJITA
AU - Hideharu AMANO
PY - 2014
DO - 10.1587/transinf.E97.D.1225
JO - IEICE TRANSACTIONS on Information
SN - 1745-1361
VL - E97-D
IS - 5
JA - IEICE TRANSACTIONS on Information
Y1 - May 2014
AB - Computational fluid dynamics (CFD) is an important tool for designing aircraft components. FaSTAR (Fast Aerodynamics Routines) is one of the most recent CFD packages and has various subroutines. However, its irregular and complicated data structure makes it difficult to execute FaSTAR on parallel machines due to memory access problem. The use of a reconfigurable platform based on field programmable gate arrays (FPGAs) is a promising approach to accelerating memory-bottlenecked applications like FaSTAR. However, even with hardware execution, a large number of pipeline stalls can occur due to read-after-write (RAW) data hazards. Moreover, it is difficult to predict when such stalls will occur because of the unstructured mesh used in FaSTAR. To eliminate this problem, we developed an out-of-order mechanism for permuting the data order so as to prevent RAW hazards. It uses an execution monitor and a wait buffer. The former identifies the state of the computation units, and the latter temporarily stores data to be processed in the computation units. This out-of-order mechanism can be applied to various types of computations with data dependency by changing the number of execution monitors and wait buffers in accordance with the equations used in the target computation. An out-of-order system can be reconfigured by automatic changing of the parameters. Application of the proposed mechanism to five subroutines in FaSTAR showed that its use reduces the number of stalls to less than 1% compared to without the mechanism. In-order execution was speeded up 2.6-fold and software execution was speeded up 2.9-fold using an Intel Core 2 Duo processor with a reasonable amount of overhead.
ER -