| Helena Kotthaus, Ingo Korb, Markus Künne and Peter Marwedel.
Performance Analysis for R: Towards a Faster R Interpreter.
In Abstract Booklet of the International R User Conference (UseR!), pages 104
Los Angeles, USA, July 2014
[BibTeX][Link]@inproceedings { kotthaus/2014b,
author = {Kotthaus, Helena and Korb, Ingo and K\"unne, Markus and Marwedel, Peter},
title = {Performance Analysis for R: Towards a Faster R Interpreter},
booktitle = {Abstract Booklet of the International R User Conference (UseR!)},
year = {2014},
pages = {104},
address = { Los Angeles, USA},
month = {jul},
url = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/kotthaus_user2014.pdf},
confidential = {n},
} |
| Helena Kotthaus, Ingo Korb, Michael Engel and Peter Marwedel.
Dynamic Page Sharing Optimization for the R Language .
In Proceedings of the 10th Symposium on Dynamic Languages, pages 79--90
Portland, Oregon, USA, October 2014
[BibTeX][PDF][Link][Abstract]@inproceedings { kotthaus/2014e,
author = {Kotthaus, Helena and Korb, Ingo and Engel, Michael and Marwedel, Peter},
title = {Dynamic Page Sharing Optimization for the R Language },
booktitle = {Proceedings of the 10th Symposium on Dynamic Languages},
year = {2014},
series = {DLS '14},
pages = {79--90},
address = {Portland, Oregon, USA},
month = {oct},
publisher = {ACM},
url = {http://dl.acm.org/citation.cfm?id=2661094},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014e_kotthaus.pdf},
confidential = {n},
abstract = {
Dynamic languages such as R are increasingly used to process .large data sets. Here, the R interpreter induces a large memory overhead due to wasteful memory allocation policies. If an application's working set exceeds the available physical memory, the OS starts to swap, resulting in slowdowns of a several orders of magnitude. Thus, memory optimizations for R will be beneficial to many applications.
Existing R optimizations are mostly based on dynamic compilation or native libraries. Both methods are futile when the OS starts to page out memory. So far, only a few, data-type or application specific memory optimizations for R exist. To remedy this situation, we present a low-overhead page sharing approach for R that significantly reduces the interpreter's memory overhead. Concentrating on the most rewarding optimizations avoids the high runtime overhead of existing generic approaches for memory deduplication or compression. In addition, by applying knowledge of interpreter data structures and memory allocation patterns, our approach is not constrained to specific R applications and is transparent to the R interpreter.
Our page sharing optimization enables us to reduce the memory consumption by up to 53.5% with an average of 18.0% for a set of real-world R benchmarks with a runtime overhead of only 5.3% on average. In cases where page I/O can be avoided, significant speedups are achieved.
},
}
Dynamic languages such as R are increasingly used to process .large data sets. Here, the R interpreter induces a large memory overhead due to wasteful memory allocation policies. If an application's working set exceeds the available physical memory, the OS starts to swap, resulting in slowdowns of a several orders of magnitude. Thus, memory optimizations for R will be beneficial to many applications.
Existing R optimizations are mostly based on dynamic compilation or native libraries. Both methods are futile when the OS starts to page out memory. So far, only a few, data-type or application specific memory optimizations for R exist. To remedy this situation, we present a low-overhead page sharing approach for R that significantly reduces the interpreter's memory overhead. Concentrating on the most rewarding optimizations avoids the high runtime overhead of existing generic approaches for memory deduplication or compression. In addition, by applying knowledge of interpreter data structures and memory allocation patterns, our approach is not constrained to specific R applications and is transparent to the R interpreter.
Our page sharing optimization enables us to reduce the memory consumption by up to 53.5% with an average of 18.0% for a set of real-world R benchmarks with a runtime overhead of only 5.3% on average. In cases where page I/O can be avoided, significant speedups are achieved.
|
| Chen-Wei Huang, Timon Kelter, Bjoern Boenninghoff, Jan Kleinsorge, Michael Engel, Peter Marwedel and Shiao-Li Tsao.
Static WCET Analysis of the H.264/AVC Decoder Exploiting Coding Information.
In International Conference on Embedded and Real-Time Computing Systems and Applications
Chongqing, China, August 2014
[BibTeX]@inproceedings { huang:2014:rtcsa,
author = {Huang, Chen-Wei and Kelter, Timon and Boenninghoff, Bjoern and Kleinsorge, Jan and Engel, Michael and Marwedel, Peter and Tsao, Shiao-Li},
title = {Static WCET Analysis of the H.264/AVC Decoder Exploiting Coding Information},
booktitle = {International Conference on Embedded and Real-Time Computing Systems and Applications},
year = {2014},
address = {Chongqing, China},
month = {August},
organization = {IEEE},
keywords = {wcet},
confidential = {n},
} |
| Andreas Heinig, Florian Schmoll, Peter Marwedel and Michael Engel.
Who's Using that Memory? A Subscriber Model for Mapping Errors to Tasks.
In Proceedings of the 10th Workshop on Silicon Errors in Logic - System Effects (SELSE)
Stanford, CA, USA, April 2014
[BibTeX][PDF][Abstract]@inproceedings { heinig:2014:SELSE,
author = {Heinig, Andreas and Schmoll, Florian and Marwedel, Peter and Engel, Michael},
title = {Who's Using that Memory? A Subscriber Model for Mapping Errors to Tasks},
booktitle = {Proceedings of the 10th Workshop on Silicon Errors in Logic - System Effects (SELSE)},
year = {2014},
address = {Stanford, CA, USA},
month = {April},
keywords = {ders},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-heinig-selse2014.pdf},
confidential = {n},
abstract = {In order to assess the robustness of software-based fault-tolerance
methods, extensive tests have to be performed that
inject faults, such as bit flips, into hardware components of a running
system. Fault injection commonly uses either system simulations, resulting
in execution times orders of magnitude longer than on real systems, or
exposes a real system to error sources like radiation. This can take place
in real time, but it enables only a very coarse-grained control over the
affected system component.
A solution combining the best characteristics from both approaches should
achieve precise fault injection in real hardware systems. The approach
presented in this paper uses the JTAG background debug facility of a CPU
to inject faults into main memory and registers of a running system. Compared
to similar earlier approaches, our solution is able to achieve rapid
fault injection using a low-cost microcontroller instead of a complex
FPGA. Consequently, our injection software is much more flexible. It
allows to restrict error injection to the execution of a set of predefined
components, resulting in a more precise control of the injection, and
also emulates error reporting, which enables the evaluation
of different error detection approaches in addition to robustness
evaluation.
},
}
In order to assess the robustness of software-based fault-tolerance
methods, extensive tests have to be performed that
inject faults, such as bit flips, into hardware components of a running
system. Fault injection commonly uses either system simulations, resulting
in execution times orders of magnitude longer than on real systems, or
exposes a real system to error sources like radiation. This can take place
in real time, but it enables only a very coarse-grained control over the
affected system component.
A solution combining the best characteristics from both approaches should
achieve precise fault injection in real hardware systems. The approach
presented in this paper uses the JTAG background debug facility of a CPU
to inject faults into main memory and registers of a running system. Compared
to similar earlier approaches, our solution is able to achieve rapid
fault injection using a low-cost microcontroller instead of a complex
FPGA. Consequently, our injection software is much more flexible. It
allows to restrict error injection to the execution of a set of predefined
components, resulting in a more precise control of the injection, and
also emulates error reporting, which enables the evaluation
of different error detection approaches in addition to robustness
evaluation.
|
| Timon Kelter and Peter Marwedel.
Parallelism Analysis: Precise WCET Values for Complex Multi-Core Systems.
In Third International Workshop on Formal Techniques for Safety-Critical Systems
Luxembourg, November 2014
[BibTeX][PDF][Link]@inproceedings { kelter:2014:ftscs,
author = {Kelter, Timon and Marwedel, Peter},
title = {Parallelism Analysis: Precise WCET Values for Complex Multi-Core Systems},
booktitle = {Third International Workshop on Formal Techniques for Safety-Critical Systems},
year = {2014},
editor = {Cyrille Artho and Peter \"Olveczky},
series = {FTSCS},
address = {Luxembourg},
month = {November},
publisher = {Springer},
url = {http://www.ftscs.org/index.php?n=Main.Home},
keywords = {wcet},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-kelter-ftscs.pdf},
confidential = {n},
} |
| Timon Kelter, Peter Marwedel and Hendrik Borghorst.
WCET-aware Scheduling Optimizations for Multi-Core Real-Time Systems.
In International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS), pages 67-74
Samos, Greece, July 2014
[BibTeX][PDF]@inproceedings { kelter:2014:samos,
author = {Kelter, Timon and Marwedel, Peter and Borghorst, Hendrik},
title = {WCET-aware Scheduling Optimizations for Multi-Core Real-Time Systems},
booktitle = {International Conference on Embedded Computer Systems: Architectures, Modeling, and Simulation (SAMOS)},
year = {2014},
pages = {67-74},
address = {Samos, Greece},
month = {July},
keywords = {wcet},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-samos.pdf},
confidential = {n},
} |
| Bjoern Dusza, Peter Marwedel, Olaf Spinczyk and Christian Wietfeld.
A Context-Aware Battery Lifetime Model for Carrier Aggregation Enabled LTE-A Systems.
In IEEE Consumer Communications and Networking Conference
Las Vegas, USA, January 2014
[BibTeX][Abstract]@inproceedings { marwedel:2014:ccnc,
author = {Dusza, Bjoern and Marwedel, Peter and Spinczyk, Olaf and Wietfeld, Christian},
title = {A Context-Aware Battery Lifetime Model for Carrier Aggregation Enabled LTE-A Systems},
booktitle = {IEEE Consumer Communications and Networking Conference},
year = {2014},
series = {CCNC},
address = {Las Vegas, USA},
month = {January},
organization = {IEEE},
keywords = {energy},
confidential = {n},
abstract = {A Quality of Experience (QoE) parameter of increasing importance is the time that a battery powered
communication device (e.g. smartphone) can be operated before it needs to be recharged. However, due to the fact that battery capacity is not evolving as fast as the power requirement, the battery lifetime of modern user equipment is
stagnating or even decreasing from one device generation to another. In parallel, a major challenge for the design of
next generation wireless systems such as LTE-Advanced (LTE-A) is that the required high portion of spectrum is not
available in a consecutive portion. For this reason, a procedure called interband non-continuous Carrier Aggregation
(CA) will be introduced in LTE-A which allows for the combination of multiple spectrum pieces from different frequency
bands. This procedure however requires the parallel operation of multiple power amplifiers that are characterized by a
high energy demand. In this paper, we quantify the impact of CA on the power consumption of LTE-A enabled communication by means of a Markovian based power consumption model that incorporates system parameters as well as context parameters. The results show that the suitability of CA does from a battery lifetime perspective strongly depend upon the actual device characteristics as well as the resource availability is the various frequency bands. Furthermore, the application of the sophisticated Kinetic Battery Model (KiBaM) shows that the charge recovery effect during idle periods does significantly affect the battery lifetime.},
}
A Quality of Experience (QoE) parameter of increasing importance is the time that a battery powered
communication device (e.g. smartphone) can be operated before it needs to be recharged. However, due to the fact that battery capacity is not evolving as fast as the power requirement, the battery lifetime of modern user equipment is
stagnating or even decreasing from one device generation to another. In parallel, a major challenge for the design of
next generation wireless systems such as LTE-Advanced (LTE-A) is that the required high portion of spectrum is not
available in a consecutive portion. For this reason, a procedure called interband non-continuous Carrier Aggregation
(CA) will be introduced in LTE-A which allows for the combination of multiple spectrum pieces from different frequency
bands. This procedure however requires the parallel operation of multiple power amplifiers that are characterized by a
high energy demand. In this paper, we quantify the impact of CA on the power consumption of LTE-A enabled communication by means of a Markovian based power consumption model that incorporates system parameters as well as context parameters. The results show that the suitability of CA does from a battery lifetime perspective strongly depend upon the actual device characteristics as well as the resource availability is the various frequency bands. Furthermore, the application of the sophisticated Kinetic Battery Model (KiBaM) shows that the charge recovery effect during idle periods does significantly affect the battery lifetime.
|
| Peter Marwedel and Michael Engel.
Flipped classroom teaching for a cyber-physical system course - an adequate presence-based learning approach in the internet age.
In Proceedings of the Tenth European Workshop on Microelectronics Education (EWME)
Tallinn, Estonia, May 2014
[BibTeX][PDF][Abstract]@inproceedings { marwedel:2014:ewme,
author = {Marwedel, Peter and Engel, Michael},
title = {Flipped classroom teaching for a cyber-physical system course - an adequate presence-based learning approach in the internet age},
booktitle = {Proceedings of the Tenth European Workshop on Microelectronics Education (EWME)},
year = {2014},
address = {Tallinn, Estonia},
month = {May},
publisher = {IEEE},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-ewme.pdf},
confidential = {n},
abstract = {In the age of the Internet, teaching styles need to take new ways of learning into account. This paper recommends the use of the flipped classroom approach. In this approach, the roles of work at home and in class are essentially swapped. We present a case study covering a course on cyber-physical system fundamentals. Results are strongly encouraging us to continue along these lines. We are also commenting on general advantages and limitations of this style of teaching.},
}
In the age of the Internet, teaching styles need to take new ways of learning into account. This paper recommends the use of the flipped classroom approach. In this approach, the roles of work at home and in class are essentially swapped. We present a case study covering a course on cyber-physical system fundamentals. Results are strongly encouraging us to continue along these lines. We are also commenting on general advantages and limitations of this style of teaching.
|
| Olaf Neugebauer, Michael Engel and Peter Marwedel.
A Parallelization Approach for Resource Restricted Embedded Heterogeneous MPSoCs Inspired by OpenMP.
In Proceedings of Software Engineering for Parallel Systems (SEPS)
2014
[BibTeX]@inproceedings { neugebauer:2014:seps,
author = {Neugebauer, Olaf and Engel, Michael and Marwedel, Peter},
title = {A Parallelization Approach for Resource Restricted Embedded Heterogeneous MPSoCs Inspired by OpenMP},
booktitle = {Proceedings of Software Engineering for Parallel Systems (SEPS)},
year = {2014},
confidential = {n},
} |
| Jan Kleinsorge and Peter Marwedel.
Computing Maximum Blocking Times with Explicit Path Analysis under Non-local Flow Bounds.
In Proceedings of the International Conference on Embedded Software (EMSOFT 2014)
New Delhi, India, October 2014
[BibTeX][Link]@inproceedings { Kleinsorge:2014:EMSOFT,
author = {Kleinsorge, Jan and Marwedel, Peter},
title = {Computing Maximum Blocking Times with Explicit Path Analysis under Non-local Flow Bounds},
booktitle = {Proceedings of the International Conference on Embedded Software (EMSOFT 2014)},
year = {2014},
series = {EMSOFT 2014},
address = {New Delhi, India},
month = {oct},
url = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-jk.pdf},
confidential = {n},
} |
| Pascal Libuschewski, Dennis Kaulbars, Dominic Siedhoff, Frank Weichert, Heinrich Müller, Christian Wietfeld and Peter Marwedel.
Multi-Objective Computation Offloading for Mobile Biosensors via LTE.
In Wireless Mobile Communication and Healthcare (Mobihealth), 2014 EAI 4th International Conference on
December 2014
[BibTeX][PDF][Link][Abstract]@inproceedings { Libuschewski/etal/2014a,
author = {Libuschewski, Pascal and Kaulbars, Dennis and Siedhoff, Dominic and Weichert, Frank and M\"uller, Heinrich and Wietfeld, Christian and Marwedel, Peter},
title = {Multi-Objective Computation Offloading for Mobile Biosensors via LTE},
booktitle = {Wireless Mobile Communication and Healthcare (Mobihealth), 2014 EAI 4th International Conference on},
year = {2014},
month = {Dec},
url = {http://dx.doi.org/10.4108/icst.mobihealth.2014.257374},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-mobihealth.pdf},
confidential = {n},
abstract = {For a rapid identification of viral epidemics a mobile virus detection is needed, which can process samples without a laboratory. The application of medical biosensors, at key positions with a high passenger volume (e.g. airports), became increasingly meaningful as epidemic early warning systems. As mobile biosensors have to fulfill various demands, like a rapid analysis and prolonged battery lifetime we present in this study a multi-objective computation offloading for mobile sensors. The decision whether it is beneficial to offload work to a server can be made automatically on the basis of contrary objectives and several constraints.},
}
For a rapid identification of viral epidemics a mobile virus detection is needed, which can process samples without a laboratory. The application of medical biosensors, at key positions with a high passenger volume (e.g. airports), became increasingly meaningful as epidemic early warning systems. As mobile biosensors have to fulfill various demands, like a rapid analysis and prolonged battery lifetime we present in this study a multi-objective computation offloading for mobile sensors. The decision whether it is beneficial to offload work to a server can be made automatically on the basis of contrary objectives and several constraints.
|
| Pascal Libuschewski, Peter Marwedel, Dominic Siedhoff and Müller Heinrich.
Multi-Objective Energy-Aware GPGPU Design Space Exploration for Medical or Industrial Applications.
In Signal-Image Technology and Internet-Based Systems (SITIS), 2014 Tenth International Conference on, pages 637-644
November 2014, doi 10.1109/SITIS.2014.11
[BibTeX][PDF][Link][Abstract]@inproceedings { Libuschewski/etal/2014b,
author = {Libuschewski, Pascal and Marwedel, Peter and Siedhoff, Dominic and Heinrich, M\"uller},
title = {Multi-Objective Energy-Aware GPGPU Design Space Exploration for Medical or Industrial Applications},
booktitle = {Signal-Image Technology and Internet-Based Systems (SITIS), 2014 Tenth International Conference on},
year = {2014},
pages = {637-644},
month = {Nov},
publisher = {IEEE Computer Society},
note = {doi 10.1109/SITIS.2014.11},
url = {dx.doi.org/10.1109/SITIS.2014.11},
file = {http://ls12-www.cs.tu-dortmund.de/daes/media/documents/publications/downloads/2014-sitis.pdf},
confidential = {n},
abstract = {This work presents a multi-objective design space exploration for Graphics Processing Units (GPUs). For any given GPGPU application, a Pareto front of best suited GPUs can be calculated. The objectives can be chosen according to the demands of the system, for example energy efficiency, run time and real-time capability. The simulated GPUs can be desktop, high performance or mobile versions. Also GPUs that do not yet exist can be modeled and simulated.
The main application area for the presented approach is the identification of suitable GPU hardware for given medical or industrial applications, e.g. for real-time process control or in healthcare sensor environments. As use case a real-time capable medical biosensor program for an automatic detection of pathogens and a wide variety of industrial, biological and physical applications were evaluated.},
}
This work presents a multi-objective design space exploration for Graphics Processing Units (GPUs). For any given GPGPU application, a Pareto front of best suited GPUs can be calculated. The objectives can be chosen according to the demands of the system, for example energy efficiency, run time and real-time capability. The simulated GPUs can be desktop, high performance or mobile versions. Also GPUs that do not yet exist can be modeled and simulated.
The main application area for the presented approach is the identification of suitable GPU hardware for given medical or industrial applications, e.g. for real-time process control or in healthcare sensor environments. As use case a real-time capable medical biosensor program for an automatic detection of pathogens and a wide variety of industrial, biological and physical applications were evaluated.
|
DAES