The European FP7 project PEPPHER is addressing programmability and performance portability for cu... more The European FP7 project PEPPHER is addressing programmability and performance portability for current and emerging heterogeneous many-core archi-tectures. As its main idea, the project proposes a multi-level parallel execution model comprised of potentially ...
Workows are considered to be one of the most relevant programming models for the Grid. In the pas... more Workows are considered to be one of the most relevant programming models for the Grid. In the past many workow languages have been developed. However, most of them are textual- oriented, are based on a self-dened notation, or lack an adequate tool-support. Therefore, there is a need for streamlining the task of Grid worklow specication. In this paper we present
International Journal of Computational Intelligence Research, 2008
Performance is one of the key features of parallel and distributed computing systems. Therefore, ... more Performance is one of the key features of parallel and distributed computing systems. Therefore, in the past a significant research effort was invested in the development of approaches for performance modeling and prediction of parallel and distributed computing systems. In this paper we identify the trends, contributions, and drawbacks of the state of the art approaches. We describe a wide range of the performance modeling approaches that spans from the highlevel mathematical modeling to the detailed instruction-level simulation. For each approach we describe how the program and machine are modeled and estimate the model development and evaluation effort, the efficiency, and the accuracy. Furthermore, we present an overall evaluation of the described approaches.
International Journal of Grid and Utility Computing, 2009
... Biographical notes: Sabri Pllana is a Senior Research Scientist at the Department of Scientif... more ... Biographical notes: Sabri Pllana is a Senior Research Scientist at the Department of Scientific Computing, University of Vienna. ... For instance, if the execution of program under study takes several weeks, we do not want to spend for evaluation of the corresponding performance ...
However, majority of Grid workflow systems either do not support Quality of Service (QoS), or pro... more However, majority of Grid workflow systems either do not support Quality of Service (QoS), or provide only partial QoS support for certain phases of the workflow lifecycle. In this paper we present Amadeus, which is a holistic service-oriented environment for QoS-aware Grid workflows. Amadeus considers user requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment workflows and the associated QoS constraints are specified at a high level using an intuitive graphical notation. A distinguishing feature of our system is the support of a comprehensive set of QoS requirements, which considers in addition to performance and economical aspects also legal and security aspects. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For improving the efficiency of workflow planning we introduce a QoS-aware workflow reduction technique. Furthermore, we present our static and dynamic planning strategies for workflow execution in accordance with user-specified requirements. For each phase of the workflow lifecycle we experimentally evaluate the corresponding Amadeus components.
Proceedings of the 34th Conference on Winter Simulation Exploring New Frontiers, 2002
The objective of upcoming research in the field of geoprocessing is to evolve interoperability st... more The objective of upcoming research in the field of geoprocessing is to evolve interoperability standards to develop flexible and scalable controlling and simulation services. In order to overcome the limitations of proprietary solutions, efforts have been made to support interoperability among simulation models and geo information systems (GIS). Existing standards in the domain of spatial information and spatial services define geoinformation (GI) in a more or less static way. Though time can be handled as an additional attribute, its representation is not explicitly specified. In contrast, as the standard for distributed heterogeneous simulation, the High Level Architecture (HLA) provides a framework for distributed time-variant simulation processes but HLA is lacking in supporting spatial information. A web-based Distributed spAtio-temporaL Interoperability architecture DALI integrating these initiatives will be presented here. The long term goal of this DALI Architecture is making standardized off-theshelf GI and simulation services usable for highly specialized simulation and controlling applications.
Performance is a key feature of large-scale computing systems. However, the achieved performance ... more Performance is a key feature of large-scale computing systems. However, the achieved performance when a certain program is executed is significantly lower than the maximal theoretical performance of the large-scale computing system. The model-based performance evaluation may be used to support the performance-oriented program development for large-scale computing systems. In this paper we present a hybrid approach for performance modeling and prediction of parallel and distributed computing systems, which combines mathematical modeling and discrete-event simulation. We use mathematical modeling to develop parameterized performance models for components of the system. Thereafter, we use discreteevent simulation to describe the structure of system and the interaction among its components. As a result, we obtain a highlevel performance model, which combines the evaluation speed of mathematical models with the structure awareness and fidelity of the simulation model. We evaluate empirically our approach with a real-world material science program that comprises more than 15,000 lines of code.
Proceedings of the Fifth International Conference on Grid and Cooperative Computing Workshops, 2006
Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for... more Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for QoS-aware Grid work- flows. Amadeus considers user’s requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment, workflows and the associated QoS constraints are specified at a high- level using an intuitive graphical notation. A set of QoS- aware
We address the issue of the development of performance models for programs that may be executed o... more We address the issue of the development of performance models for programs that may be executed on large-scale computing systems. The commonly used approaches apply non-standard notations for model specification and often require that the software engineer has a thorough understanding of the underlying performance modeling technique. We propose to bridge the gap between the performance modeling and software engineering
Many important scientific and engineering problems may be solved by combining multiple applicatio... more Many important scientific and engineering problems may be solved by combining multiple applications in the form of a Grid workflow. We consider that for the wide acceptance of Grid technology it is important that the user has the possibility to express requirements on Quality of Service (QoS) at workflow specification time. However, most of the existing workflow languages lack constructs for QoS specification. In this paper we present an approach for high level workflow specification that considers a comprehensive set of QoS requirements. Besides performance related QoS, it includes economical, legal and security aspects. For instance, for security or legal reasons the user may express the location affinity regarding Grid resources on which certain workflow tasks may be executed. Our QoS-aware workflow system provides support for the whole workflow life cycle from specification to execution. Workflow is specified graphically, in an intuitive manner, based on a standard visual modeling language. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For reducing the complexity of workflow planning, we introduce a QoS-aware workflow reduction technique. We illustrate our approach with a real-world workflow for maxillo facial surgery simulation.
The improvement of single-processor performance by increasing clock rate and instructions-per-clo... more The improvement of single-processor performance by increasing clock rate and instructions-per-clock number has reached its technological limits. Increasing instead the number of processing cores per chip is an alternative that can yield better overall system ...
2008 International Conference on Complex, Intelligent and Software Intensive Systems, 2008
Performance is a key feature of large-scale computing systems. However, the achieved performance ... more Performance is a key feature of large-scale computing systems. However, the achieved performance when a certain program is executed is significantly lower than the maximal theoretical performance of the large-scale computing system. The model-based performance evaluation may be used to support the performance-oriented program development for large-scale computing systems. In this paper we present a hybrid approach for performance modeling and prediction of parallel and distributed computing systems, which combines mathematical modeling and discrete-event simulation. We use mathematical modeling to develop parameterized performance models for components of the system. Thereafter, we use discreteevent simulation to describe the structure of system and the interaction among its components. As a result, we obtain a highlevel performance model, which combines the evaluation speed of mathematical models with the structure awareness and fidelity of the simulation model. We evaluate empirically our approach with a real-world material science program that comprises more than 15,000 lines of code.
2012 Design, Automation & Test in Europe Conference & Exhibition (DATE), 2012
We discuss three complementary approaches that can provide both portability and an increased leve... more We discuss three complementary approaches that can provide both portability and an increased level of abstraction for the programming of heterogeneous multicore systems. Together, these approaches also support performance portability, as currently investigated in the EU FP7 project PEPPHER. In particular, we consider (1) a library-based approach, here represented by the integration of the SkePU C++ skeleton programming library with the StarPU runtime system for dynamic scheduling and dynamic selection of suitable execution units for parallel tasks; (2) a language-based approach, here represented by the Offload-C++ high-level language extensions and Offload compiler to generate platform-specific code; and (3) a componentbased approach, specifically the PEPPHER component system for annotating user-level application components with performance metadata, thereby preparing them for performance-aware composition. We discuss the strengths and weaknesses of these approaches and show how they could complement each other in an integrational programming framework for heterogeneous multicore systems.
2012 SC Companion: High Performance Computing, Networking Storage and Analysis, 2012
ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhan... more ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhance performance portability and programmability of heterogeneous multi-core systems. Its primary target is single-node heterogeneous systems, where several CPU cores are supported by accelerators such as GPUs. This poster briefly surveys the PEPPHER framework for singlenode systems, and elaborates on the prospectives for leveraging the PEPPHER approach to generate performance-portable code for heterogeneous multi-node systems.
2012 SC Companion: High Performance Computing, Networking Storage and Analysis, 2012
ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhan... more ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhance performance portability and programmability of heterogeneous multi-core systems. Its primary target is single-node heterogeneous systems, where several CPU cores are supported by accelerators such as GPUs. This poster briefly surveys the PEPPHER framework for single-node systems, and elaborates on the prospectives for leveraging the PEPPHER approach to generate performance-portable code for heterogeneous multi-node systems.
First International Conference on Complex, Intelligent and Software Intensive Systems (CISIS'07), 2007
Performance is one of the key features of parallel and distributed computing systems. Therefore, ... more Performance is one of the key features of parallel and distributed computing systems. Therefore, in the past a significant research effort was invested in the development of approaches for performance modeling and prediction of parallel and distributed computing systems. In this paper we identify the trends, contributions, and drawbacks of the state of the art approaches. We describe a wide
2006 Fifth International Conference on Grid and Cooperative Computing Workshops, 2006
Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for... more Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for QoS-aware Grid work- flows. Amadeus considers user’s requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment, workflows and the associated QoS constraints are specified at a high- level using an intuitive graphical notation. A set of QoS- aware
The European FP7 project PEPPHER is addressing programmability and performance portability for cu... more The European FP7 project PEPPHER is addressing programmability and performance portability for current and emerging heterogeneous many-core archi-tectures. As its main idea, the project proposes a multi-level parallel execution model comprised of potentially ...
Workows are considered to be one of the most relevant programming models for the Grid. In the pas... more Workows are considered to be one of the most relevant programming models for the Grid. In the past many workow languages have been developed. However, most of them are textual- oriented, are based on a self-dened notation, or lack an adequate tool-support. Therefore, there is a need for streamlining the task of Grid worklow specication. In this paper we present
International Journal of Computational Intelligence Research, 2008
Performance is one of the key features of parallel and distributed computing systems. Therefore, ... more Performance is one of the key features of parallel and distributed computing systems. Therefore, in the past a significant research effort was invested in the development of approaches for performance modeling and prediction of parallel and distributed computing systems. In this paper we identify the trends, contributions, and drawbacks of the state of the art approaches. We describe a wide range of the performance modeling approaches that spans from the highlevel mathematical modeling to the detailed instruction-level simulation. For each approach we describe how the program and machine are modeled and estimate the model development and evaluation effort, the efficiency, and the accuracy. Furthermore, we present an overall evaluation of the described approaches.
International Journal of Grid and Utility Computing, 2009
... Biographical notes: Sabri Pllana is a Senior Research Scientist at the Department of Scientif... more ... Biographical notes: Sabri Pllana is a Senior Research Scientist at the Department of Scientific Computing, University of Vienna. ... For instance, if the execution of program under study takes several weeks, we do not want to spend for evaluation of the corresponding performance ...
However, majority of Grid workflow systems either do not support Quality of Service (QoS), or pro... more However, majority of Grid workflow systems either do not support Quality of Service (QoS), or provide only partial QoS support for certain phases of the workflow lifecycle. In this paper we present Amadeus, which is a holistic service-oriented environment for QoS-aware Grid workflows. Amadeus considers user requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment workflows and the associated QoS constraints are specified at a high level using an intuitive graphical notation. A distinguishing feature of our system is the support of a comprehensive set of QoS requirements, which considers in addition to performance and economical aspects also legal and security aspects. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For improving the efficiency of workflow planning we introduce a QoS-aware workflow reduction technique. Furthermore, we present our static and dynamic planning strategies for workflow execution in accordance with user-specified requirements. For each phase of the workflow lifecycle we experimentally evaluate the corresponding Amadeus components.
Proceedings of the 34th Conference on Winter Simulation Exploring New Frontiers, 2002
The objective of upcoming research in the field of geoprocessing is to evolve interoperability st... more The objective of upcoming research in the field of geoprocessing is to evolve interoperability standards to develop flexible and scalable controlling and simulation services. In order to overcome the limitations of proprietary solutions, efforts have been made to support interoperability among simulation models and geo information systems (GIS). Existing standards in the domain of spatial information and spatial services define geoinformation (GI) in a more or less static way. Though time can be handled as an additional attribute, its representation is not explicitly specified. In contrast, as the standard for distributed heterogeneous simulation, the High Level Architecture (HLA) provides a framework for distributed time-variant simulation processes but HLA is lacking in supporting spatial information. A web-based Distributed spAtio-temporaL Interoperability architecture DALI integrating these initiatives will be presented here. The long term goal of this DALI Architecture is making standardized off-theshelf GI and simulation services usable for highly specialized simulation and controlling applications.
Performance is a key feature of large-scale computing systems. However, the achieved performance ... more Performance is a key feature of large-scale computing systems. However, the achieved performance when a certain program is executed is significantly lower than the maximal theoretical performance of the large-scale computing system. The model-based performance evaluation may be used to support the performance-oriented program development for large-scale computing systems. In this paper we present a hybrid approach for performance modeling and prediction of parallel and distributed computing systems, which combines mathematical modeling and discrete-event simulation. We use mathematical modeling to develop parameterized performance models for components of the system. Thereafter, we use discreteevent simulation to describe the structure of system and the interaction among its components. As a result, we obtain a highlevel performance model, which combines the evaluation speed of mathematical models with the structure awareness and fidelity of the simulation model. We evaluate empirically our approach with a real-world material science program that comprises more than 15,000 lines of code.
Proceedings of the Fifth International Conference on Grid and Cooperative Computing Workshops, 2006
Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for... more Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for QoS-aware Grid work- flows. Amadeus considers user’s requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment, workflows and the associated QoS constraints are specified at a high- level using an intuitive graphical notation. A set of QoS- aware
We address the issue of the development of performance models for programs that may be executed o... more We address the issue of the development of performance models for programs that may be executed on large-scale computing systems. The commonly used approaches apply non-standard notations for model specification and often require that the software engineer has a thorough understanding of the underlying performance modeling technique. We propose to bridge the gap between the performance modeling and software engineering
Many important scientific and engineering problems may be solved by combining multiple applicatio... more Many important scientific and engineering problems may be solved by combining multiple applications in the form of a Grid workflow. We consider that for the wide acceptance of Grid technology it is important that the user has the possibility to express requirements on Quality of Service (QoS) at workflow specification time. However, most of the existing workflow languages lack constructs for QoS specification. In this paper we present an approach for high level workflow specification that considers a comprehensive set of QoS requirements. Besides performance related QoS, it includes economical, legal and security aspects. For instance, for security or legal reasons the user may express the location affinity regarding Grid resources on which certain workflow tasks may be executed. Our QoS-aware workflow system provides support for the whole workflow life cycle from specification to execution. Workflow is specified graphically, in an intuitive manner, based on a standard visual modeling language. A set of QoS-aware service-oriented components is provided for workflow planning to support automatic constraint-based service negotiation and workflow optimization. For reducing the complexity of workflow planning, we introduce a QoS-aware workflow reduction technique. We illustrate our approach with a real-world workflow for maxillo facial surgery simulation.
The improvement of single-processor performance by increasing clock rate and instructions-per-clo... more The improvement of single-processor performance by increasing clock rate and instructions-per-clock number has reached its technological limits. Increasing instead the number of processing cores per chip is an alternative that can yield better overall system ...
2008 International Conference on Complex, Intelligent and Software Intensive Systems, 2008
Performance is a key feature of large-scale computing systems. However, the achieved performance ... more Performance is a key feature of large-scale computing systems. However, the achieved performance when a certain program is executed is significantly lower than the maximal theoretical performance of the large-scale computing system. The model-based performance evaluation may be used to support the performance-oriented program development for large-scale computing systems. In this paper we present a hybrid approach for performance modeling and prediction of parallel and distributed computing systems, which combines mathematical modeling and discrete-event simulation. We use mathematical modeling to develop parameterized performance models for components of the system. Thereafter, we use discreteevent simulation to describe the structure of system and the interaction among its components. As a result, we obtain a highlevel performance model, which combines the evaluation speed of mathematical models with the structure awareness and fidelity of the simulation model. We evaluate empirically our approach with a real-world material science program that comprises more than 15,000 lines of code.
2012 Design, Automation & Test in Europe Conference & Exhibition (DATE), 2012
We discuss three complementary approaches that can provide both portability and an increased leve... more We discuss three complementary approaches that can provide both portability and an increased level of abstraction for the programming of heterogeneous multicore systems. Together, these approaches also support performance portability, as currently investigated in the EU FP7 project PEPPHER. In particular, we consider (1) a library-based approach, here represented by the integration of the SkePU C++ skeleton programming library with the StarPU runtime system for dynamic scheduling and dynamic selection of suitable execution units for parallel tasks; (2) a language-based approach, here represented by the Offload-C++ high-level language extensions and Offload compiler to generate platform-specific code; and (3) a componentbased approach, specifically the PEPPHER component system for annotating user-level application components with performance metadata, thereby preparing them for performance-aware composition. We discuss the strengths and weaknesses of these approaches and show how they could complement each other in an integrational programming framework for heterogeneous multicore systems.
2012 SC Companion: High Performance Computing, Networking Storage and Analysis, 2012
ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhan... more ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhance performance portability and programmability of heterogeneous multi-core systems. Its primary target is single-node heterogeneous systems, where several CPU cores are supported by accelerators such as GPUs. This poster briefly surveys the PEPPHER framework for singlenode systems, and elaborates on the prospectives for leveraging the PEPPHER approach to generate performance-portable code for heterogeneous multi-node systems.
2012 SC Companion: High Performance Computing, Networking Storage and Analysis, 2012
ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhan... more ABSTRACT PEPPHER is a 3-year EU FP7 project that develops a novel approach and framework to enhance performance portability and programmability of heterogeneous multi-core systems. Its primary target is single-node heterogeneous systems, where several CPU cores are supported by accelerators such as GPUs. This poster briefly surveys the PEPPHER framework for single-node systems, and elaborates on the prospectives for leveraging the PEPPHER approach to generate performance-portable code for heterogeneous multi-node systems.
First International Conference on Complex, Intelligent and Software Intensive Systems (CISIS'07), 2007
Performance is one of the key features of parallel and distributed computing systems. Therefore, ... more Performance is one of the key features of parallel and distributed computing systems. Therefore, in the past a significant research effort was invested in the development of approaches for performance modeling and prediction of parallel and distributed computing systems. In this paper we identify the trends, contributions, and drawbacks of the state of the art approaches. We describe a wide
2006 Fifth International Conference on Grid and Cooperative Computing Workshops, 2006
Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for... more Abstract In this paper we present Amadeus, which is a holis- tic service-oriented environment for QoS-aware Grid work- flows. Amadeus considers user’s requirements, in terms of QoS constraints, during workflow specification, planning, and execution. Within the Amadeus environment, workflows and the associated QoS constraints are specified at a high- level using an intuitive graphical notation. A set of QoS- aware
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Papers by Sabri Pllana