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Improving Accuracy of Software Performance Models on Multicore Platforms with Shared Caches
Babka, Vlastimil ; Tůma, Petr (advisor) ; Eeckhout, Lieven (referee) ; Black-Schaffer, David (referee)
The context of this work are performance models of software systems, which are used for predicting performance of a system in its design phase. For this purpose, performance models capture the explicit interactions of software components that make up the system, and the resource demands of primitive actions performed by the components. On contemporary hardware platforms, the software components however interact also through implicit sharing of numerous resources such as processor caches, which influence the performance of the primitive actions. Implicit resource sharing is often omitted in performance models, which affects their prediction accuracy. In this work we introduce two methods for including resource sharing models in performance models. Next, we propose an approximate resource sharing model based on linear regression, and a detailed model for predicting performance impact of cache sharing. The cache model is validated on a real processor and its design is preceded by extensive experiments which investigate the performance aspects of cache sharing. In addition, we introduce a method for robust validation of performance models using many automatically generated applications.
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Extending Java Performance Monitoring Framework with Support for Linux Performance Data Sources
Júnoš, Peter ; Bulej, Lubomír (advisor) ; Babka, Vlastimil (referee)
Title: Extending Java Performance Monitoring Framework with Support for Linux Performance Data Sources Author: Peter Júnoš Department: Department of Distributed and Dependable Systems Supervisor: Ing. Lubomír Bulej, Ph.D Abstract: Java Perfomance Measurement Framework (JPMF) is a library, that is able to hook into program and gain performance information in given watchpoints. Notable drawback of currect implementation are missing sen- sors, that would be able to measure performance statistics related to stor- age, CPU, memory and network interfaces under Linux. Linux does not provide unified way of accessing such performance statis- tics. They can be accessed using virtual file systems, syscalls and netlink interface. The goal of this work is extending JPMF, so that it will provide measurement of mentioned performance statistics in a Linux-specific way. Keywords: performance measurement, JPMF, Linux, netlink stats, procfs stats 1
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HelenOS ext4 filesystem driver
Princ, František ; Děcký, Martin (advisor) ; Babka, Vlastimil (referee)
HelenOS is an experimental operating system based on microkernel. It's developed by people related to Faculty of Mathematics and Physics at Charles University in Prague. The present implementantion is prepared to support a scale of filesystems because of VFS abstraction, but actually only a few of filesystems are supported. Ext4 is modern filesystem, developed Linux kernel developers. The previous releases ext2 and especially ext3 are still very popular in many Linux distributions. Imple- mentation of ext2/3/4 filesystems can be also found in other unix-based operating systems, for example *BSD or OpenSolaris. The main goal of this thesis is to extend HelenOS operating system to support previously mentioned filesystems.
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Stability and Security of ZlomekFS
Záloha, Jan ; Babka, Vlastimil (advisor) ; Podzimek, Andrej (referee)
- english version ZlomekFS is a distributed filesystem which is able to share data among nodes. These nodes can cooperate in various modes. Modes differ in caching of local data at the client side and in the way how data is synchronized between the client and the server. This synchronization has been implemented by an unsecured and untrusted network connection until now. The current implementation uses FUSE interface for the communication between the kernel of the filesystem and the user. The synchronization is triggered when the user performs a specific operation above the filesystem. For well functionality in modern network environment it is necessary to both communicating partners to be sure about the identity of the second end of a communicating channel. This thesis implements trustworthy connection between the server and the client part of filesystem. In addition, it separates machine and user type of client. Next important part of the thesis is correct data synchronization and precise definition of sharing semantics.
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Forensic RAM dump image analyzer
Kollár, Ivor ; Holub, Viliam (advisor) ; Babka, Vlastimil (referee)
While different techniques are used for physical memory dumping, most of them provide a hard-to-analyse image of raw data. The aim of the work is to develop an automatic analyser of physical memory dumps retrieving contained information in a user-friendly form. The analyser is supposed to simplify automatic data extraction and should be used by forensic experts. Among expected features are multiple target architecture/OS support, target architecture/OS guessing, automated password/crypto keys collecting, process listing, and module/driver listing.
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Task snapshoting in HelenOS
Brambora, Tomáš ; Děcký, Martin (advisor) ; Babka, Vlastimil (referee)
HelenOS is a modern micro-kernel based operating system being developed at the Faculty of Mathematics and Physics of the Charles University in Prague. Application checkpointing is a feature which is primarily used for adding fault tolerance to computing systems, however, it can also be used as a basis for process migration. HelenOS has not been developed with support for application checkpointing in mind; the aim of this thesis is to explore the possibilities of adding such support to HelenOS and provide a prototype implemetation.
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History and Backup Support for zlomekFS
Wartiak, Rastislav ; Babka, Vlastimil (advisor) ; Marek, Lukáš (referee)
zlomekFS is a distributed file system that supports disconnected operation using local cache. During synchronization of local changes it offers easytouse conflict resolution mechanism. Further improved it became a file system with no specific kernel code. It has therefore a good potential in future public use. As the content of this file system can be updated by many users, keeping history of the changes can be a useful feature. This thesis implements file versioning in zlomekFS, answering the questions such as how to store and access the history. On top of the versioning, the possibility of consistent backup is introduced into the file system. New functionality is derived from the analysis of other file systems with similar features and selection of the most suitable approach for zlomekFS.
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Syllable-based PPM
Unger, Lukáš ; Babka, Vlastimil (referee) ; Lánský, Jan (advisor)
PPM is an adaptive comprimation method which works with the data's context. During PPM compression, a tree of contexts of maximum length k is built based on the already processed part of the file, which is then used to predict the probability of the next character using variablelength context of maximum length k. Codes are then assigned to different characters based on these probabilities. The goal of this work is the implementation of a syllable-based version of a PPM algorithm and comparison of it's results with symbol-based and word-based versions. This work is based on the implementation of a syllable parser as described in [7].
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Interactive Data Visualization Tool
Fabian, Peter ; Babka, Vlastimil (referee) ; Parízek, Pavel (advisor)
The goal of the work was to design and implement a tool, which would allow the users to work with a graphical representation of statistic data easily in an interactive manner. The IVP tool supports both the basic adjustments of graphs and advanced modifications, which are either very hard or impossible to achieve in similar tools. However, the key feature of the tool is its extensibility. The particular graph types and the interactive features are implemented as plug-ins and their functionality is provided to the tool's core. The thesis also presents a description of the IVP tool's implementation details, user documentation, an overview of the existing graphing software and its comparison to the IVP tool.
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