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SaS Seminars

Software and Systems Research Seminar Series


The SaS Seminars are a permanent series of open seminars of the Division of Software and Systems (SaS) at the Department of Computer and Information Science (IDA), Linköping University. The objective of the seminars is to present outstanding research and ideas/problems relevant for SaS present and future activities. In particular, seminars cover the SaS research areas software engineering, programming environments, system software, embedded SW/HW systems, computer systems engineering, realtime systems, parallel and distributed computing, and theoretical computer science. - Two kinds of seminars are planned:

  • talks by invited speakers not affiliated with SaS,

  • internal seminars presenting lab research to whole SaS.

The speakers are expected to give a broad perspective of the presented research, adressing the audience with a general computer science background but possibly with no specific knowledge in the domain of the presented research. The normal length of a presentation is 60 minutes, including discussion.

The SaS seminars are coordinated by Christoph Kessler.



Recent / Upcoming SaS Seminars (2015)



Resource Contention Management in Virtualized Systems

Diwakar Krishnamurthy, Associate Professor, University of Calgary, Canada

Friday, 13 March 2015, 13:15, room Alan Turing

Remark: This seminar is a joint SaS/ADIT seminar.

Abstract:
Public and private cloud computing environments employ virtualization methods to consolidate application workloads onto shared servers. Modern servers typically have one or more sockets each with one or more computing cores, a multi-level caching hierarchy, a memory subsystem, and an interconnect to the memory of other sockets. While resource management methods may manage application performance by controlling the sharing of processing time and input-output rates, there is generally no management of contention for virtualization kernel resources or for the memory hierarchy and subsystems. Yet such contention can have a significant impact on application performance. Hardware platform specific counters have been used for detecting such contention. In this talk, we show that such counters alone may not be always sufficient for detecting contention. We propose a software probe based approach for detecting and mitigating contention for shared platform resources. Results from a private cloud and a public cloud show that the probe imposes a low overhead and is remarkably effective at detecting and mitigating performance degradations due to resource contention over a wide variety of workload scenarios and platform architectures.

Bio:
Diwakar Krishnamurthy is currently an associate professor and director of the software engineering program in the department of electrical and computer engineering at the University of Calgary, Calgary, Canada. His research interests are broadly focused on computer systems performance evaluation. In the past, his research team has contributed techniques to test, model, optimize, and manage the performance of enterprise application systems. He is currently involved in projects related to runtime management of cloud systems, simulation techniques for studying healthcare systems, and big data systems. His research has been supported by HP Labs and SAP Research.



Combating Unpredictability in Multicores through the Multi-Resource Server

Dr. Rafia Inam, Mälardalen Univ., Sweden

Wednesday, 25 Feb. 2015, 13:15, room John von Neumann

Abstract:
This seminar presents challenges that hinder the predictable integration and execution of real-time applications on multicore platforms. It presents how shared resources, like CPU, memory-bus bandwidth, caches, and memory cause unpredictability and interference. We propose to adapt the traditional server-based scheduling approach on the multicore platforms with additional resource-reservations to control the shared access to such resources and present the multi-resource server (MRS) as a solution such that the execution of real-time applications becomes predictable.
A multi-resource server uses resource reservation for both CPU bandwidth and memory-bus bandwidth to bound the interferences between tasks running on the same core, as well as, between tasks running on different cores. The latter could, without MRS, interfere with each other due to contention on a shared memory-bus and memory. The results indicate that MRS can be used to "encapsulate" legacy systems and to give them enough resources to fulfill their purpose. Further, the compositional schedulability analysis for MRS is also provided and an experimental study is performed to bring insight on the correlation between the server budgets.
Keywords: Hierarchical scheduling, memory-bus bandwidth, cache coloring, memory-bank partitioning.

Speaker's bio:
Rafia Inam recently obtained a PhD degree from Mälardalen University, Sweden. Her PhD research was on hierarchical scheduling for real-time embedded systems. A main focus of her work is on predictable execution of real-time systems for unicore and multicore platforms.



Network Challenges in Cyber-Physical Systems

Prof. Luis Almeida, U. Porto, Portugal, and Mälardalen Univ., Sweden

Tuesday, 27 Jan. 2015, 13:15, room John von Neumann

Abstract:
Cyber-Physical Systems (CPS) frequently rely on networking infrastructures. These necessarily play a central role in supporting the needed system-wide properties, being timeliness a particularly important one as dictated by the dynamics of the associated physical processes. In this talk, we present the case for flexible channel reservation-based communication as a means to provide scalable, open and adaptive latency-constrained communication and thus enable an efficient design of emerging CPS applications, such as Remote Interactions, Collaborative Robotics and other CPS applications with variable and unanticipated bandwidth requirements.

Speaker's bio:
Luis Almeida is an associate professor at the ECE Dep. of the University of Porto and a member of the Institute of Telecommunications in Porto where he coordinates the Distributed and Real-Time Embedded Systems group, working in real-time communication protocols and middleware for embedded systems and cooperative robotics. Currently he is also guest professor at the School of Innovation, Design and Engineering of Mälardalen University, in the Embedded Systems Division.







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Page responsible: Christoph Kessler
Last updated: 2015-02-25