Serialization of threads due to critical sections is a fundamental bottleneck to achieving high performance in multithreaded programs. Dynamically, such serialization may be unnecessary because these critical sections...
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Serialization of threads due to critical sections is a fundamental bottleneck to achieving high performance in multithreaded programs. Dynamically, such serialization may be unnecessary because these critical sections could have safely executed concurrently without locks. Current processors cannot fully exploit such parallelism because they do not have mechanisms to dynamically detect such false inter-thread dependences. We propose Speculative Lock Elision (SLE), a novel micro-architectural technique to remove dynamically unnecessary lock-induced serialization and enable highly concurrent multithreaded execution. the key insight is that locks do not always have to be acquired for a correct execution. Synchronization instructions are predicted as being unnecessary and elided. this allows multiple threads to concurrently execute critical sections protected by the same lock. Misspeculation due to inter-thread data conflicts is detected using existing cache mechanisms and rollback is used for recovery. Successful speculative elision is validated and committed without acquiring the lock. SLE can be implemented entirely in microarchitecture without instruction set support and without system-level modifications, is transparent to programmers, and requires only trivial additional hardware support. SLE can provide programmers a fast path to writing correct high-performance multithreaded programs.
Health care systems are known to be quite complex in structure and operation. the technology of liver transplantation is one of the aspects of health care systems that has always been difficult to grasp. the main prob...
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ISBN:
(纸本)0769510922
Health care systems are known to be quite complex in structure and operation. the technology of liver transplantation is one of the aspects of health care systems that has always been difficult to grasp. the main problem with liver transplantation is the fact that it is not easy to study using traditional quantitative tools. the paper demonstrates the use of discrete event simulation as an explorative tool to help stakeholders to understand the behavior of the system so that they can achieve informed decisions with regard to the prioritization of patients waiting for transplantation. the paper also shows the construction of a tailor-made package (LiverSim) and provides an example of how this package is used by the stakeholders to assist in the evaluation process. Some final lessons are drawn that simulation helps in exploring more issues outside the boundaries of quantitative results.
Load imbalance is the most important factor that limits scalability of parallel applications in scientific computing. Dynamic load balancing at the application level usually is implemented in a proprietary manner. thi...
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ISBN:
(纸本)0769510922
Load imbalance is the most important factor that limits scalability of parallel applications in scientific computing. Dynamic load balancing at the application level usually is implemented in a proprietary manner. this paper presents a generic framework for application level dynamic load balancing. Our framework can be applied to any grid-based iterative numerical simulation. It defines a programming model that is tailored to the specific requirements of this class of applications and that provides a unique API for shared and distributed memory systems and combinations thereof. Load balancing can be implemented totally transparent to the application. the framework also provides an interface to application developers who wish to steer load balancing based on their specific knowledge of the computation. third party repartitioning software can be integrated easily. We apply our framework to PAM-CRASH, an industrial crash simulation software marketed by ESI that is widely used in the automotive industry. Our project results are evaluated at BMW's crash simulation department on a network of SGI cc-NUMA systems.
During the ITiCSE 2002 conference in Århus, Denmark, a panel presentation on the topic of import to and export from computing Science Education and other fields focused on the case of Mathematics Education Resear...
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ISBN:
(纸本)9781581136487
During the ITiCSE 2002 conference in Århus, Denmark, a panel presentation on the topic of import to and export from computing Science Education and other fields focused on the case of Mathematics Education Research. the outcome was very successful, withthe panelists' presentations giving rise to active audience *** withthe theme from the earlier panel, this proposal suggests a similar format withthe expanded theme of transfer into computing Science Education from Science Education Research. this panel will look at how research theories developed in the context of various areas of science education can be applied to computing Science Education as well as ways in which computing science educational theories may be used in those areas. Because computing Science Education is a young discipline, it is still in search of its research framework [2]. In formulating such a framework, it can be practical and productive to adapt approaches from research in other disciplines, both educational and related areas. At the same time, the younger discipline can offer innovative new approaches to the older *** panelists will examine possibilities and difficulties in some import and export attempts between several areas of Science Education Research and computing Science Education. For this context, science is considered to include mathematics.
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