1,379 research outputs found
Towards a deeper understanding of hybrid programming
No full textWith the end of Dennard scaling, future high performance computers are expected to consist of distributed nodes that comprise more cores with direct access to shared memory on a node. However, many parallel applications still use a pure message-passing programming model based on the message-passing interface (MPI). Thereby, they potentially do not make optimal use of shared memory resources. The pure message-passing approach---as argued in this work---is not necessarily the best fit to current and future supercomputing architectures. In this thesis, I therefore present a detailed performance analysis of so-called hybrid programming models that aim at improving performance by combining a shared memory model with the message-passing model on current symmetric multiprocessor (SMP) systems.
First, inter-node communication performance is investigated in the context of (hybrid) message-passing programs. A novel performance model for estimating communication performance on current SMP nodes is presented. As is demonstrated, in contrast to the typically used classic postal performance model, the new model allows to more accurately predict inter-node communication performance in the presence of simultaneously communicating processes and saturation of the network interface controller on current multicore architectures. The implications of the new model on hybrid programs are discussed. In addition, I demonstrate the (current) difficulties of multithreaded MPI communication based on results obtained for a multithreaded ping pong benchmark.
Moreover, I show how intra-node MPI communication performance can significantly be improved upon for small to medium size messages by saving message-passing overhead and/or superior cache usage. This is achieved through a direct copy in shared memory using either the hybrid MPI+MPI or the MPI+OpenMP programming method.
Furthermore, I contrast and evaluate several (pure and hybrid) implementation options for a structured grid sparse matrix-vector multiplication in depth. These choices differ in how hybrid parallelism is exploited at the application level (coarse-grained vs. fine-grained problem decomposition) and with respect to the hybrid programming systems (pure MPI vs. MPI+MPI vs. MPI+OpenMP). I discuss their performance factors such as locality, overhead, efficient use of MPI's derived datatypes, and the serial fraction in Amdahl's law. Moreover, I experimentally demonstrate how a coarse-grained hybrid application design can be used to control these factors, resulting in significant performance improvements (compared to a pure MPI parallelization) in communication and/or synchronization for both the hybrid MPI+MPI and MPI+OpenMP parallel programming approaches for different grid decompositions.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-08-01The student, Philipp Samfass, accepted the attached license on 2016-07-15 at 15:00.The student, Philipp Samfass, submitted this Thesis for approval on 2016-07-15 at 15:14.This Thesis was approved for publication on 2016-07-18 at 10:36.DSpace SAF Submission Ingestion Package generated from Vireo submission #9967 on 2016-11-10 at 12:20:53Made available in DSpace on 2016-11-10T18:27:54Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-07-18Embargo set by: Seth Robbins for item 95379
Lift date: 2018-11-10T18:28:02Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemU of I Only Restriction set for Item 95379 on 2018-08-08T16:35:25Z with date 2020-08-08 by [email protected] of I Only Restriction set for Item 95379 on 2018-08-08T16:35:47Z with date 2020-08-08 by [email protected] of I Only Restriction set for Item 95379 on 2020-07-23T17:55:31Z with date 2022-08-08 by [email protected] of I Only Restriction set for Item 95379 on 2020-07-23T17:55:42Z with date 2022-08-08 by [email protected] of I Only Restriction set for Item 95379 on 2020-07-23T17:55:55Z with date 2022-08-08 by [email protected] of I Only Restriction set for Item 95379 on 2022-02-21T20:54:42Z with date 2024-02-21 by [email protected] of I Only Restriction set for Item 95379 on 2022-02-21T20:54:56Z with date 2024-02-21 by [email protected] of I Only Restriction set for Item 95379 on 2022-02-21T20:55:02Z with date 2024-02-21 by [email protected] College Thesis Office and IDEALS Team approved extension request from author to change restriction to U of I Access for a period of two years. Implemented by [email protected] on 2022-02-21 at 2:54 PM CDTU of I Onl
Philipp Melanchthon
No full textPhilipp Melanchthon (1497–1560) was, with Martin Luther, the most influential reformer of the church during the 16th century. He was also a reformer of university education, especially theological studies, as well as the school system in Germany. He was responsible for a theological curriculum that included Greek, Hebrew, and philosophy. He, as a professor of Greek at the University of Wittenberg since 1518, was the author of the first generally accepted Protestant confession, known as the Confessio Augustana (1530). He also wrote the first Protestant commentaries on Paul’s letter to the Romans (1519), as well as the first Protestant handbook in systematic theology (1521). He was the main negotiator of the Protestant movement during the diets and religious discussions with the Roman Catholic Church. He is known as the ‘teacher of Germany and Europe’ and is respected as the father of the ecumenical movement. Yet, Melanchthon is not known to South Africans and especially Afrikaans-speaking people who, traditionally, have close links with the reformational tradition. There is not yet one single publication on Melanchthon in Afrikaans or by a South African scholar, making this book, therefore, the first by an Afrikaans-speaking scholar on Melanchthon
#Bitcoin : an analysis of the field of a decentralized virtual currency using twitter data
No full textAuthor Philipp AllerstorferAbstract in englischer SpracheMasterarbeit Universität Linz 201
Extension of the Finite Volume Solver SWE towards the Non-Hydrostatic Shallow Water Equations
No full text
Towards a deeper understanding of hybrid programming
No full textWith the end of Dennard scaling, future high performance computers are expected to consist of distributed nodes that comprise more cores with direct access to shared memory on a node. However, many parallel applications still use a pure message-passing programming model based on the message-passing interface (MPI). Thereby, they potentially do not make optimal use of shared memory resources. The pure message-passing approach---as argued in this work---is not necessarily the best fit to current and future supercomputing architectures. In this thesis, I therefore present a detailed performance analysis of so-called hybrid programming models that aim at improving performance by combining a shared memory model with the message-passing model on current symmetric multiprocessor (SMP) systems.
First, inter-node communication performance is investigated in the context of (hybrid) message-passing programs. A novel performance model for estimating communication performance on current SMP nodes is presented. As is demonstrated, in contrast to the typically used classic postal performance model, the new model allows to more accurately predict inter-node communication performance in the presence of simultaneously communicating processes and saturation of the network interface controller on current multicore architectures. The implications of the new model on hybrid programs are discussed. In addition, I demonstrate the (current) difficulties of multithreaded MPI communication based on results obtained for a multithreaded ping pong benchmark.
Moreover, I show how intra-node MPI communication performance can significantly be improved upon for small to medium size messages by saving message-passing overhead and/or superior cache usage. This is achieved through a direct copy in shared memory using either the hybrid MPI+MPI or the MPI+OpenMP programming method.
Furthermore, I contrast and evaluate several (pure and hybrid) implementation options for a structured grid sparse matrix-vector multiplication in depth. These choices differ in how hybrid parallelism is exploited at the application level (coarse-grained vs. fine-grained problem decomposition) and with respect to the hybrid programming systems (pure MPI vs. MPI+MPI vs. MPI+OpenMP). I discuss their performance factors such as locality, overhead, efficient use of MPI's derived datatypes, and the serial fraction in Amdahl's law. Moreover, I experimentally demonstrate how a coarse-grained hybrid application design can be used to control these factors, resulting in significant performance improvements (compared to a pure MPI parallelization) in communication and/or synchronization for both the hybrid MPI+MPI and MPI+OpenMP parallel programming approaches for different grid decompositions.U of I OnlyGraduate College Thesis Office approved request from author to change restriction to U of I Access for a period of two years. Implemented by [email protected] on 2018-08-08 at 11:35 AM CD
On Philipp Lersch’s Psychology, Reflection No. 2
No full textАвтор статті зазначає, що у 1930–1970 рр. Ф. Лерш був головним представником гуманітарної течії в німецькомовній психології. Наукову класифікацію людських прагнень і стремлінь було
викладено у головній праці Ф. Лерша «Структура особи» (11-те видання 1970 року). Ф. Лерш зумів
об’єднати у своїм творі інформацію із низки наук (біології, психопатології, із різних психологічних
теорій та концепцій).The author of the article notes that in 1930-1970, Philipp Lersch was the main representative of the
humanitarian direction in German psychology. A scientific classification of human aspirations and ambitions
was described in the main work by Philipp Lersch “Building the Person” (11th ed. of 1970). In his work,
Philipp Lersch managed to combine information from a number of sciences (biology, psychopathology, various
psychological theories and concepts)
Deformation Behavior and Damage Modeling of Polypropylene and Polycarbonate
No full textAuthor Philipp Siegfried StelzerKurzfassungen in deutscher und englischer SpracheMasterarbeit Universität Linz 201
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