Global memory optimisation for embedded systems allowed by code duplication

ACM Trans. Des. Autom. Electron. Syst.

Palkovic²,

Hamers

et al. 2009

Self Cite

131

115

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publicationCitation for published version (APA): Gheorghita, S. V., Palkovic, M., Hamers, J., Vandecappelle, A., Mamagkakis, S., Basten, T., ... Bosschere, . System scenario based design of dynamic embedded systems. (ES reports; Vol. 2007-06). Eindhoven: Technische Universiteit Eindhoven. General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. In the past decade, real-time embedded systems have become much more complex due to the introduction of a lot of new functionality in one application, and due to running multiple applications concurrently. This increases the dynamic nature of today's applications and systems, and tightens the requirements for their constraints in terms of deadlines and energy consumption. State-of-theart design methodologies try to cope with these novel issues by identifying several most used cases and dealing with them separately, reducing the newly introduced complexity. This paper presents a generic and systematic design-time/run-time methodology for handling the dynamic nature of modern embedded systems, which can be utilized by existing design methodologies to increase their efficiency. It is based on the concept of system scenarios, which group system behaviors that are similar from a multi-dimensional cost perspective, such as resource requirements, delay, and energy consumption, in such a way that the system can be configured to exploit this cost similarity. At design-time, these scenarios are individually optimized. Mechanisms for predicting the current scenario at run-time and for switching between scenarios are ...

Section: Memory Access Optimizationmentioning

confidence: 99%

System-scenario-based design of dynamic embedded systems

ACM Trans. Des. Autom. Electron. Syst.

Palkovic²,

Hamers

et al. 2009

Self Cite

131

115

“…Other approaches that consider application scenarios to optimize a design include [22,23,28]. In [28], the authors concentrate on saving energy for a single task application.…”

Section: Related Workmentioning

confidence: 99%

“…It is not clear how scenarios are predicted at runtime. To reduce the number of memory accesses, in [23], the authors selectively duplicate parts of application source code, enabling global loop transformations across data dependent conditions. They have a systematic way of detecting the most important application behaviors based on profiling and of clustering them into scenarios based on a trade-off between the number of memory accesses and the code size increase.…”

Section: Related Workmentioning

confidence: 99%

“…The paper presents a method to map a multitask application communication to a network on chip architecture, satisfying the design constraints of each individual scenario. Most of the mentioned papers (except [23]) emphasize on how the scenarios are exploited for obtaining a more optimized design and do not go into detail on how to select and predict scenarios. Our work focuses on these last two problems.…”

Section: Related Workmentioning

confidence: 99%

See 1 more Smart Citation

Scenario Selection and Prediction for DVS-Aware Scheduling of Multimedia Applications

J Sign Process Syst Sign Image

Basten

Corporaal

2007

Abstract. Modern multimedia applications usually have real-time constraints and they are implemented using application-domain specific embedded processors. Dimensioning a system requires accurate estimations of resources needed by the applications. Overestimation leads to over-dimensioning. For a good resource estimation, all the cases in which an application can run must be considered. To avoid an explosion in the number of different cases, those that are similar with respect to required resources are combined into, so called application scenarios. This paper presents a methodology and a tool that can automatically detect the most important variables from an application and use them to select and dynamically predict scenarios, with respect to the necessary time budget, for soft real-time multimedia applications. The tool was tested for three multimedia applications. Using a proactive scenario-based dynamic voltage scheduler based on the scenarios and the runtime predictor generated by our tool, the energy consumption decreases with up to 19%, while guaranteeing a frame deadline miss ratio close to zero.

“…6 This work combines profiling with the geometrical model to find the optimal scenarios for global memory optimizations. The idea is similar to hyperblock scheduling, but on a much coarser level.…”

mentioning

confidence: 99%

Application Scenarios in Streaming-Oriented Embedded-System Design

IEEE Des. Test. Comput.

Basten

Corporaal

2008

Self Cite

&EMBEDDED SYSTEMS USUALLY consist of processors that execute domainspecific applications. Much of their functionality is implemented in software, which runs on one or multiple processors, leaving only the high-performance functions implemented in hardware. Most typical embedded systems (such as TVs, cellular phones, and MP3 players) run multimedia or telecom applications that exhibit dynamic behavior, and their execution costs (such as the number of cycles and energy) depend on the input data. Moreover, these applications are often implemented as a main loop, called the loop of interest, that is executed over and over again, reading, processing, and writing out individual stream objects (see Figure 1). A stream object could be a bit belonging to a compressed bitstream representing a coded video clip, or it could be a macroblock, video frame, audio sample, or network package. Usually, these applications must deliver a given throughput (number of objects per second), which imposes a time constraint on each loop iteration. The read part of the loop of interest takes a stream object from the input stream and separates it into a header and the object's data. The processing part consists of several kernels. The write part sends the processed data to output devices, such as a screen or speakers, and saves the application's internal state for further use; for example, in a video decoder, the previous decoded frame might be necessary to decode the current frame. The dynamism existing in modern applications leads to the use of different kernels for each stream object, depending on the object type. The actions executed in a particular loop iteration form the application's internal operation mode.In this article, we describe a method that provides a systematic way of detecting and exploiting, at design time and runtime, the different internal operation modes. The fact that applications have different internal operation modes has not been fully exploited in embedded-system design thus far. Our approach combines a static analysis and profiling of the system at design time with information collected at runtime about the system's environment. By knowing a system's possible operation modes and information about their resource consumption at design time, it is possible to make specific and aggressive design decisions for each operation mode at different design steps.To avoid complexity problems, we cluster the operation modes that are closely related to one another from a resource consumption perspective in application scenarios, distinguishing the truly different operation modes via different scenarios. It is then possible to derive a faster or lower-energy implementation (for example, by using different source-code optimizations per scenario) or a better estimation of required resources (such as the number of computation cycles or bandwidth). This leads to a smaller, lessexpensive, and more energy-efficient system that can deliver the required performance. 581A design method for handling increasingly dynamic real-time embeddeds...