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Title: Efficiency Evaluation of Cray XT Parallel IO Stack

Abstract

PetaScale computing platforms need to be coupled with efficient IO subsystems that can deliver commensurate IO throughput to scientific applications. In order to gain insights into the deliverable IO efficiency on the Cray XT platform at ORNL, this paper presents an in-depth efficiency evaluation of its parallel IO software stack. Our evaluation covers the performance of a variety of parallel IO interfaces, including POSIX IO, MPI-IO, and HDF5. Moreover, we describe several tuning parameters for these interfaces and present their effectiveness in enhancing the IO efficiency.

Authors:
 [1];  [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Computational Sciences
Sponsoring Org.:
USDOE
OSTI Identifier:
1261242
DOE Contract Number:
AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: Cray User Group Conference, Seattle, WA, USA, 20070507, 20070510
Country of Publication:
United States
Language:
English

Citation Formats

Yu, Weikuan, Oral, H Sarp, Vetter, Jeffrey S, and Barrett, Richard F. Efficiency Evaluation of Cray XT Parallel IO Stack. United States: N. p., 2007. Web.
Yu, Weikuan, Oral, H Sarp, Vetter, Jeffrey S, & Barrett, Richard F. Efficiency Evaluation of Cray XT Parallel IO Stack. United States.
Yu, Weikuan, Oral, H Sarp, Vetter, Jeffrey S, and Barrett, Richard F. Mon . "Efficiency Evaluation of Cray XT Parallel IO Stack". United States. doi:.
@article{osti_1261242,
title = {Efficiency Evaluation of Cray XT Parallel IO Stack},
author = {Yu, Weikuan and Oral, H Sarp and Vetter, Jeffrey S and Barrett, Richard F},
abstractNote = {PetaScale computing platforms need to be coupled with efficient IO subsystems that can deliver commensurate IO throughput to scientific applications. In order to gain insights into the deliverable IO efficiency on the Cray XT platform at ORNL, this paper presents an in-depth efficiency evaluation of its parallel IO software stack. Our evaluation covers the performance of a variety of parallel IO interfaces, including POSIX IO, MPI-IO, and HDF5. Moreover, we describe several tuning parameters for these interfaces and present their effectiveness in enhancing the IO efficiency.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

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  • Parallel IO over Cray XT is supported by a vendor-supplied MPI-IO package. This package contains a proprietary ADIO implementation built on top of the sysio library. While it is reasonable to maintain a stable code base for application scientists' convenience, it is also very important to the system developers and researchers to analyze and assess the effectiveness of parallel IO software, and accordingly, tune and optimize the MPI-IO implementation. A proprietary parallel IO code base relinquishes such flexibilities. On the other hand, a generic UFS-based MPI-IO implementation is typically used on many Linux-based platforms. We have developed an open-source MPI-IOmore » package over Lustre, referred to as OPAL (OPportunistic and Adaptive MPI-IO Library over Lustre). OPAL provides a single source-code base for MPI-IO over Lustre on Cray XT and Linux platforms. Compared to Cray implementation, OPAL provides a number of good features, including arbitrary specification of striping patterns and Lustre-stripe aligned file domain partitioning. This paper presents the performance comparisons between OPAL and Cray's proprietary implementation. Our evaluation demonstrates that OPAL achieves the performance comparable to the Cray implementation. We also exemplify the benefits of an open source package in revealing the underpinning of the parallel IO performance.« less
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  • Abstract not provided.
  • Scientific applications use input/output (I/O) for obtaining initial conditions and execution parameters, as a persistent way of saving program output, and for safeguarding against system unreliability. Although system sizes are expected to continue increasing, I/O performance is not expected to keep pace with system computation and communication performance. Understanding application I/O demands and system I/O capabilities is the first step toward bridging this gap between them. In this paper, we present our approach for characterizing the I/O demands of applications on the Cray XT. We also present preliminary case studies showing the use of our I/O characterization infrastructure with climatemore » studies and combustion simulation programs.« less
  • Performance, debugging, and administration tools are critical for the effective use of parallel computing platforms, but traditional tools have failed to overcome several problems that limit their scalability, such as communication between a large number of tool processes and the management and processing of the volume of data generated on a large number of compute nodes. A tree-based overlay network has proven effective for overcoming these challenges. In this paper, we present our experiences in bringing our MRNet tree-based overlay network infrastructure to the Cray XT platform, including a description of proof-of-concept tools that use MRNet on the Cray XT.