| 1. |
- Kågström, Simon, et al.
(författare)
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A novel method for adding multiprocessor support to a large and complex uniprocessor kernel
- 2004
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Konferensbidrag (refereegranskat)abstract
- Summary form only given. The current trend of using multiprocessor computers for server applications requires operating system adoptions for high performance. However, modifying large bodies of software is very costly and time-consuming, and the cost of porting an operating system to a multiprocessor might not be motivated by the potential performance benefits. We present a novel method, the application kernel approach, for adaption of an existing uniprocessor kernel to SMP hardware. Our approach considers the existing kernel as a "black box", to which no or small changes are made. Instead, the original kernel runs OS-services unmodified on one processor whereas the other processors execute applications on top of a small custom kernel. A prototype implementation illustrates that the approach can be realized with fairly small resources. We also present an initial performance evaluation where we show that the performance is good for user-bound applications.
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| 2. |
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| 3. |
- Kågström, Simon, et al.
(författare)
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Cibyl : an Environment for Language Diversity on Mobile Devices
- 2007
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Konferensbidrag (refereegranskat)abstract
- With an estimated installation base of around 1 billion units, the Java J2ME platform is one of the largest development targets available. For mobile devices, J2ME is often the only available environment. For the very large body of software written in C other languages, this means difficult and costly porting to another language to support J2ME devices. This paper presents the Cibyl programming environment which allows existing code written in C and other languages supported by GCC to be recompiled into Java bytecode and run with close to native Java performance on J2ME devices. Cibyl translates compiled MIPS binaries into Java bytecode. In contrast to other approaches, Cibyl supports the full C language, is based on unmodified standard tools, and does not rely on source code conversion. To achieve good performance, Cibyl employs extensions to the MIPS architecture to support low-overhead calls to native Java functionality and use knowledge of the MIPS ABI to avoid computing unused values and transfer unnecessary registers. An evaluation on multiple virtual machines shows that Cibyl achieves performance similar to native Java, with results ranging from a slowdown of around to a speedup of over 9 depending on the JVM and the benchmark.
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| 4. |
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| 5. |
- Kågström, Simon, et al.
(författare)
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Optimizations in the Cibyl binary translator for J2ME devices
- 2008
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Konferensbidrag (refereegranskat)abstract
- The Java J2ME platform is one of the largest software platforms available, and often the only available development platform for mobile phones, which is a problem when porting C or C++ applications. The Cibyl binary translator targets this problem, translating MIPS binaries into Java bytecode to run on J2ME devices. This paper presents the optimization framework used by Cibyl to provide compact and well-performing translated code. Cibyl optimizes expensive multiplications/divisions, floating point support, function co-location to Java methods and provides a peephole optimizer. The paper also evaluates Cibyl performance both in a real-world GPS navigation application where the optimizations increase display update frequency with around 15% and a comparison against native Java and the NestedVM binary translator where we show that Cibyl can provide significant advantages for common code patterns.
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| 6. |
- Kågström, Simon
(författare)
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Performance and Implementation Complexity in Multiprocessor Operating System Kernels
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing use of multiprocessor computers require operating system adaptations to take advantage of the computing power. However, porting an operating system kernel to run on a multiprocessor can be very difficult because of a large code base, concurrency issues when dealing with multiple threads of execution, and limited tool support for development. Likewise, it can be difficult to obtain good performance from a ported operating system without sufficient parallelism in the operating system kernel. This thesis examines the tradeoff between performance and implementation complexity in multiprocessor operating system ports and is based on four papers. The first paper is a survey of existing multiprocessor implementation approaches and focuses on the tradeoff between performance and implementation effort. The second paper describes experiences from performing a traditional lock-based multiprocessor port while the third paper presents an alternative porting approach which aims to minimize implementation complexity. The fourth paper, finally, presents a tool for efficient instrumentation of programs, which can be used during the development of large software systems such as operating system kernels. The main contribution of this thesis is an in-depth investigation into the techniques used when porting operating systems to multiprocessors, focusing on implementation complexity and performance. The traditional approach used in the second paper required longer development time than expected, and the alternative approach in the third paper can therefore be preferable in some cases. The need for efficient tools is also illustrated in the fourth paper.
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| 7. |
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| 8. |
- Kågström, Simon, et al.
(författare)
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The Design and Implementation of Multiprocessor Support for an Industrial Operating System Kernel
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The ongoing transition from uniprocessor to multiprocessor computers requires support from the operating system kernel. Although many general-purpose multiprocessor operating systems exist, there is a large number of specialized operating systems which require porting in order to work on multiprocessors. In this paper we describe the multiprocessor port of a cluster operating system kernel from a producer of industrial systems. Our initial implementation uses a giant locking scheme that serializes kernel execution. We also employed a method in which CPU-local variables are placed in a special section mapped to per-CPU physical memory pages. The giant lock and CPU-local section allowed us to implement an initial working version with only minor changes to the original code, although the giant lock and kernel-bound applications limit the performance of our multiprocessor port. Finally, we also discuss experiences from the implementation.
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| 9. |
- Kågström, Simon, et al.
(författare)
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The Design and Implementation of Multiprocessor Support for an Industrial Operating System Kernel
- 2009
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Ingår i: International Journal of Computers and Their Applications. - 1076-5204. ; 16:1, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- The ongoing transition from uniprocessor to multi-core computers requires support from the operating system kernel. Although many general-purpose multiprocessor operating systems exist, there is a large number of specialized operating systems which require porting in order to work on multiprocessors. In this paper we describe the multiprocessor port of a cluster operating system kernel from a producer of industrial systems. Our initial implementation uses a giant locking scheme that serializes kernel execution. We also employed a method in which CPU-local variables are placed in a special section mapped to per-CPU physical memory pages. The giant lock and CPU-local section allowed us to implement an initial working version with only minor changes to the original code, although the giant lock and kernel-bound applications limit the performance of our multiprocessor port. Finally, we also discuss experiences from the implementation.
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| 10. |
- Kågström, Simon
(författare)
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Tools, Techniques, and Trade-offs when Porting Large Software Systems to New Environments
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Computer hardware and software evolve very fast. With the advent of chip-multiprocessors and symmetric multithreading, multiprocessor hardware configurations are becoming prevalent. For software, new hardware and requirements such as security, performance and maintainability drive the development of new runtime environments, virtual machines and programming methodologies. These trends present problems when porting legacy software. Multiprocessor hardware require ports of uniprocessor operating system kernels while new software environments might require that programs have to be ported to different languages. This thesis examines the tradeoff between performance and development effort for software porting with case studies in operating system porting to multiprocessors and tool support for porting C and C++ applications to Java virtual machines. The thesis consists of seven papers. The first paper is a survey of existing multiprocessor development approaches and focuses on the tradeoff between performance and implementation effort. The second and third papers describe the evolution a traditional lock-based multiprocessor port, going from a serialized “giant locked” port and evolving into a coarse-grained implementation. The fourth paper instead presents an alternative porting approach which aims to minimize development effort. The fifth paper describes a tool for efficient instrumentation of programs, which can be used during the development of large software systems such as operating system kernels. The sixth and seventh papers finally describe a binary translator which translates MIPS binaries into Java bytecode to allow low-effort porting of C and C++ applications to Java virtual machines. The first main contributions of this thesis is an in-depth investigation of the techniques used when porting operating system kernels to multiprocessors, focusing on development effort and performance. The traditional approach used in the second and third papers required longer development time than expected, and the alternative approach in the fourth paper can therefore be preferable in some cases. The second main contribution is the development of a binary translator that targets portability of C and C++ applications to J2ME devices. The last two papers show that the approach is functional and has good enough performance to be feasible in real-life situations.
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