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Memory Positioning of Real-Time Code for Smaller Worst-Case Execution Times

Amine Marref, Adam Betts
2011 2011 16th IEEE International Conference on Engineering of Complex Computer Systems  
The process of determining the worst-case execution time (WCET) is challenged in the presence of caches due to their unpredictable effect on the speed of memory references.  ...  Experimental evaluation of our proposed analysis shows that the proposed analysis successfully identified code positioning that yields the minimum WCET for over half of the problems within manageable time  ...  ACKNOWLEDGEMENTS This work is supported by the Swedish Foundation for Strategic Research (SSF) through the Research Centre for Predictable Embedded Software Systems (PROGRESS).  ... 
doi:10.1109/iceccs.2011.10 dblp:conf/iceccs/MarrefB11 fatcat:tya24qfu6bbovack7iqlkpazha

Multicore-Aware Code Co-Positioning to Reduce WCET on Dual-Core Processors with Shared Instruction Caches

Yiqiang Ding, Wei Zhang
2012 Journal of Computing Science and Engineering  
For real-time systems it is important to obtain the accurate worst-case execution time (WCET).  ...  Our experiments indicate that the proposed multicore-aware code positioning approaches, not only improve the worstcase performance of the real-time threads but also make good tradeoffs between efficiency  ...  improving the worst-case execution time for real-time tasks.  ... 
doi:10.5626/jcse.2012.6.1.12 fatcat:cgkbu7oqovhi7itfbvzsegpql4

Scratchpad memories vs locked caches in hard real-time systems: a quantitative comparison

Isabelle Puaut, Christophe Pais
2007 2007 Design, Automation & Test in Europe Conference & Exhibition  
Experimental results show that the algorithm yields to good ratios of on-chip memory accesses on the worst-case execution path, with a tolerable reload overhead, for both types of on-chip memories.  ...  The contents of on-chip memory, although selected off-line, is changed at run-time, for the sake of scalability with respect to task size.  ...  For that reason, many schedulability analysis methods rely on the knowledge of an upper bound for the execution times of tasks (WCETs, for Worst-Case Execution Times).  ... 
doi:10.1109/date.2007.364510 fatcat:fgu4iiirnvh3np7m4oolwlhpwy

Static extraction of memory access profiles for multi-core interference analysis of real-time tasks [article]

Thomas Carle, Hugues Cassé
2021 arXiv   pre-print
Our method analyzes tasks in isolation at the binary level and generates worst-case timing and memory access profiles.  ...  We present a static analysis framework for real-time task systems running on multi-core processors.  ...  Conclusion and future works We presented the TIPs framework: a collection of models and algorithms for the extraction of precise timing and memory access profiles of real-time tasks.  ... 
arXiv:2103.17082v1 fatcat:kw4b2sqi7vfnbdm6bhf4ujpcjm

Composable Virtual Memory for an Embedded SoC

Cor Meenderinck, Anca Molnos, Kees Goossens
2012 2012 15th Euromicro Conference on Digital System Design  
Systems on a Chip concurrently execute multiple applications that may start and stop at run-time, creating many use-cases.  ...  Our virtual memory is also predictable, for applications with real-time constraints. We integrated the virtual memory on, CompSOC, an existing composable SoC prototyped in FPGA.  ...  Figure 1 : 1 Single executable for worst-case use-case vs. executable per application when using Virtual Memory (VM). Figure 3 : 3 Memory virtualisation inside a tile.  ... 
doi:10.1109/dsd.2012.32 dblp:conf/dsd/MeenderinckMG12 fatcat:znsrpqcbtfe47huiunvbqmkgiy

WCET-driven cache-aware code positioning

Heiko Falk, Helena Kotthaus
2011 Proceedings of the 14th international conference on Compilers, architectures and synthesis for embedded systems - CASES '11  
We present a novel cache-aware code positioning optimization driven by worst-case execution time (WCET) information.  ...  Code positioning is able to decrease the accumulated cache misses for a total of 18 real-life benchmarks by 15.5% on average for an automotive processor featuring a 2-way setassociative cache.  ...  The authors would also like to thank Synopsys for the provision of the instruction set simulator CoMET enabling the determination of ACETs.  ... 
doi:10.1145/2038698.2038722 dblp:conf/cases/FalkK11 fatcat:2iutx2pbf5e3rirfji2xmpnquu

WCET-aware register allocation based on graph coloring

Heiko Falk
2009 Proceedings of the 46th Annual Design Automation Conference on ZZZ - DAC '09  
This paper extends a graph coloring register allocator such that it uses precise worst-case execution time (WCET) models.  ...  Many compilers heuristically decide when and where to spill a register to memory, without having a clear understanding of the impact of such spill code on a program's run time.  ...  Acknowledgments The authors would like to thank AbsInt Angewandte Informatik GmbH for their support concerning WCET analysis using aiT (www.absint.com/ait).  ... 
doi:10.1145/1629911.1630100 dblp:conf/dac/Falk09 fatcat:odwkc545u5cptnab5a4z3vgxai

High-level programming of embedded hard real-time devices

Filip Pizlo, Lukasz Ziarek, Ethan Blanton, Petr Maj, Jan Vitek
2010 Proceedings of the 5th European conference on Computer systems - EuroSys '10  
We show that Java with a concurrent, real-time garbage collector, can have throughput close to that of C programs and comes within 10% in the worst observed case on realistic benchmark.  ...  We provide a detailed breakdown of the costs of Java features and their execution times and compare to real-time and throughput-optimized commercial Java virtual machines.  ...  The authors thank Tomas Kalibera and Gaith Haddad for their work on the CDx benchmark, the anonymous reviewers and Gilles Muller for their helpful comments.  ... 
doi:10.1145/1755913.1755922 dblp:conf/eurosys/PizloZBMV10 fatcat:vi2wb3lexbg5fcplpfplu2ln74

WCET-driven Cache-based Procedure Positioning Optimizations

Paul Lokuciejewski, Heiko Falk, Peter Marwedel
2008 2008 Euromicro Conference on Real-Time Systems  
We present two novel positioning optimizations driven by worst-case execution time (WCET) information to effectively minimize the program's worst-case behavior.  ...  In standard literature, these positioning techniques are guided by execution profile data and focus on an improved average-case performance.  ...  Acknowledgments The authors would like to thank AbsInt Angewandte Informatik GmbH for their support concerning WCET analysis using the aiT framework.  ... 
doi:10.1109/ecrts.2008.20 dblp:conf/ecrts/LokuciejewskiFM08 fatcat:cu43krpy6ngczdoelvcqtpdsnu

Combining Worst-Case Timing Models, Loop Unrolling, and Static Loop Analysis for WCET Minimization

Paul Lokuciejewski, Peter Marwedel
2009 2009 21st Euromicro Conference on Real-Time Systems  
Our novel optimization is driven by worst-case execution time (WCET) information to effectively minimize the program's worst-case behavior.  ...  In this paper, we present loop unrolling that is tailored towards real-time systems.  ...  Timing constraints deserve special attention for embedded systems that often operate as real-time systems. Worst-case timing behavior is expressed by the worst-case execution time.  ... 
doi:10.1109/ecrts.2009.9 dblp:conf/ecrts/LokuciejewskiM09 fatcat:ed5c7ckgg5bnzebs3ke5fyvtsm

Measurement-Based Timing Analysis of the AURIX Caches

Leonidas Kosmidis, Davide Compagnin, David Morales, Enrico Mezzetti, Eduardo Quinones, Jaume Abella, Tullio Vardanega, Francisco J. Cazorla, Marc Herbstritt
2016 Worst-Case Execution Time Analysis  
Cache memories are one of the hardware resources with higher potential to reduce worst-case execution time (WCET) costs for software programs with tight real-time constraints.  ...  Authors thank Benjamin Lesage for his support in execution time collection infrastructure on the AURIX board.  ...  our target platform) and relatively smaller caches (16KB for code and 8KB for data in our target platform), possibly disabled by default.  ... 
doi:10.4230/oasics.wcet.2016.9 dblp:conf/wcet/KosmidisCMMQAVC16 fatcat:awexh4rsb5ejvohifxta7jaxlq

Time-predictable memory arbitration for a Java chip-multiprocessor

Christof Pitter
2008 Proceedings of the 6th international workshop on Java technologies for real-time and embedded systems - JTRES '08  
In this paper, we propose an approach to calculate worst-case execution times (WCET) of tasks running on a homogeneous Java multiprocessor. These processors access a shared main memory.  ...  This memory arbitration allows calculating upper bounds for the execution time of Java bytecodes depending on the number of CPUs, the size of the time slot, and the memory access time.  ...  Therefore, the worst-case execution time (WCET) of each task in the system has to be known. The WCET is the maximum execution time of a piece of code.  ... 
doi:10.1145/1434790.1434808 dblp:conf/jtres/Pitter08 fatcat:tyach4o7nvgkfiri74xcv6ch3a

Patmos: a time-predictable microprocessor

Martin Schoeberl, Wolfgang Puffitsch, Stefan Hepp, Benedikt Huber, Daniel Prokesch
2018 Real-time systems  
This paper presents a way out of this dilemma: a processor designed for real-time systems.  ...  Current processors provide high average-case performance, as they are optimized for general purpose computing. However, those optimizations often lead to a high worst-case execution time (WCET).  ...  This work is part of the project "Hard Real-Time Embedded Multiprocessor Platform -RTEMP" and received partial funding from the Danish Research Council for Technology and Production Sciences under contract  ... 
doi:10.1007/s11241-018-9300-4 fatcat:werexvn555bz5mhw7o2fia2abu

Preemption Points Placement for Sporadic Task Sets

Marko Bertogna, Giorgio Buttazzo, Mauro Marinoni, Gang Yao, Francesco Esposito, Marco Caccamo
2010 2010 22nd Euromicro Conference on Real-Time Systems  
To achieve this goal, preemptions are allowed only at selected points of the code of each task, decreasing the preemption overhead and simplifying the estimation of worst-case execution parameters.  ...  In this paper, a method is presented for the optimal placement of preemption points under simplifying conditions, namely, a fixed preemption overhead at each point.  ...  Worst-case execution times The worst-case execution time C i of a task τ i is the largest amount of processor time a job of τ i might need to successfully complete its execution.  ... 
doi:10.1109/ecrts.2010.9 dblp:conf/ecrts/BertognaBMYEC10 fatcat:sl54rcyu7jec5m4fjjl3vu5mey

A framework to experiment optimizations for real-time and embedded software [article]

Hugues Cassé , Jonathan Ponroy, Olivier Zendra
2010 arXiv   pre-print
To meet these requirements, it may be necessary to improve the software by applying various kinds of transformations like compiler optimizations, specific mapping of code and data in the available memories  ...  For this purpose, we have developed a common framework that makes it possible to experiment various code transfor-mations and to evaluate their impact of various criteria.  ...  OTAWA is a library dedicated to the analysis of Worst-Case Execution Times for hard real-time tasks.  ... 
arXiv:1011.6031v1 fatcat:qtlhyegrj5gazkpzpy2w6exzpi
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