Kernel Development: How Things Go Wrong
Total Page:16
File Type:pdf, Size:1020Kb

Load more
Recommended publications
-
Shorten Device Boot Time for Automotive IVI and Navigation Systems
Shorten Device Boot Time for Automotive IVI and Navigation Systems Jim Huang ( 黃敬群 ) <[email protected]> Dr. Shi-wu Lo <[email protected]> May 28, 2013 / Automotive Linux Summit (Spring) Rights to copy © Copyright 2013 0xlab http://0xlab.org/ [email protected] Attribution – ShareAlike 3.0 Corrections, suggestions, contributions and translations You are free are welcome! to copy, distribute, display, and perform the work to make derivative works Latest update: May 28, 2013 to make commercial use of the work Under the following conditions Attribution. You must give the original author credit. Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one. For any reuse or distribution, you must make clear to others the license terms of this work. Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above. License text: http://creativecommons.org/licenses/by-sa/3.0/legalcode Goal of This Presentation • Propose a practical approach of the mixture of ARM hibernation (suspend to disk) and Linux user-space checkpointing – to shorten device boot time • An intrusive technique for Android/Linux – minimal init script and root file system changes are required • Boot time is one of the key factors for Automotive IVI – mentioned by “Linux Powered Clusters” and “Silver Bullet of Virtualization (Pitfalls, Challenges and Concerns) Continued” at ALS 2013 – highlighted by “Boot Time Optimizations” at ALS 2012 About this presentation • joint development efforts of the following entities – 0xlab team - http://0xlab.org/ – OSLab, National Chung Cheng University of Taiwan, led by Dr. -
Proceedings 2005
LAC2005 Proceedings 3rd International Linux Audio Conference April 21 – 24, 2005 ZKM | Zentrum fur¨ Kunst und Medientechnologie Karlsruhe, Germany Published by ZKM | Zentrum fur¨ Kunst und Medientechnologie Karlsruhe, Germany April, 2005 All copyright remains with the authors www.zkm.de/lac/2005 Content Preface ............................................ ............................5 Staff ............................................... ............................6 Thursday, April 21, 2005 – Lecture Hall 11:45 AM Peter Brinkmann MidiKinesis – MIDI controllers for (almost) any purpose . ....................9 01:30 PM Victor Lazzarini Extensions to the Csound Language: from User-Defined to Plugin Opcodes and Beyond ............................. .....................13 02:15 PM Albert Gr¨af Q: A Functional Programming Language for Multimedia Applications .........21 03:00 PM St´ephane Letz, Dominique Fober and Yann Orlarey jackdmp: Jack server for multi-processor machines . ......................29 03:45 PM John ffitch On The Design of Csound5 ............................... .....................37 04:30 PM Pau Arum´ıand Xavier Amatriain CLAM, an Object Oriented Framework for Audio and Music . .............43 Friday, April 22, 2005 – Lecture Hall 11:00 AM Ivica Ico Bukvic “Made in Linux” – The Next Step .......................... ..................51 11:45 AM Christoph Eckert Linux Audio Usability Issues .......................... ........................57 01:30 PM Marije Baalman Updates of the WONDER software interface for using Wave Field Synthesis . 69 02:15 PM Georg B¨onn Development of a Composer’s Sketchbook ................. ....................73 Saturday, April 23, 2005 – Lecture Hall 11:00 AM J¨urgen Reuter SoundPaint – Painting Music ........................... ......................79 11:45 AM Michael Sch¨uepp, Rene Widtmann, Rolf “Day” Koch and Klaus Buchheim System design for audio record and playback with a computer using FireWire . 87 01:30 PM John ffitch and Tom Natt Recording all Output from a Student Radio Station . -
Study of File System Evolution
Study of File System Evolution Swaminathan Sundararaman, Sriram Subramanian Department of Computer Science University of Wisconsin {swami, srirams} @cs.wisc.edu Abstract File systems have traditionally been a major area of file systems are typically developed and maintained by research and development. This is evident from the several programmer across the globe. At any point in existence of over 50 file systems of varying popularity time, for a file system, there are three to six active in the current version of the Linux kernel. They developers, ten to fifteen patch contributors but a single represent a complex subsystem of the kernel, with each maintainer. These people communicate through file system employing different strategies for tackling individual file system mailing lists [14, 16, 18] various issues. Although there are many file systems in submitting proposals for new features, enhancements, Linux, there has been no prior work (to the best of our reporting bugs, submitting and reviewing patches for knowledge) on understanding how file systems evolve. known bugs. The problems with the open source We believe that such information would be useful to the development approach is that all communication is file system community allowing developers to learn buried in the mailing list archives and aren’t easily from previous experiences. accessible to others. As a result when new file systems are developed they do not leverage past experience and This paper looks at six file systems (Ext2, Ext3, Ext4, could end up re-inventing the wheel. To make things JFS, ReiserFS, and XFS) from a historical perspective worse, people could typically end up doing the same (between kernel versions 1.0 to 2.6) to get an insight on mistakes as done in other file systems. -
Linux on the Road
Linux on the Road Linux with Laptops, Notebooks, PDAs, Mobile Phones and Other Portable Devices Werner Heuser <wehe[AT]tuxmobil.org> Linux Mobile Edition Edition Version 3.22 TuxMobil Berlin Copyright © 2000-2011 Werner Heuser 2011-12-12 Revision History Revision 3.22 2011-12-12 Revised by: wh The address of the opensuse-mobile mailing list has been added, a section power management for graphics cards has been added, a short description of Intel's LinuxPowerTop project has been added, all references to Suspend2 have been changed to TuxOnIce, links to OpenSync and Funambol syncronization packages have been added, some notes about SSDs have been added, many URLs have been checked and some minor improvements have been made. Revision 3.21 2005-11-14 Revised by: wh Some more typos have been fixed. Revision 3.20 2005-11-14 Revised by: wh Some typos have been fixed. Revision 3.19 2005-11-14 Revised by: wh A link to keytouch has been added, minor changes have been made. Revision 3.18 2005-10-10 Revised by: wh Some URLs have been updated, spelling has been corrected, minor changes have been made. Revision 3.17.1 2005-09-28 Revised by: sh A technical and a language review have been performed by Sebastian Henschel. Numerous bugs have been fixed and many URLs have been updated. Revision 3.17 2005-08-28 Revised by: wh Some more tools added to external monitor/projector section, link to Zaurus Development with Damn Small Linux added to cross-compile section, some additions about acoustic management for hard disks added, references to X.org added to X11 sections, link to laptop-mode-tools added, some URLs updated, spelling cleaned, minor changes. -
Membrane: Operating System Support for Restartable File Systems Swaminathan Sundararaman, Sriram Subramanian, Abhishek Rajimwale, Andrea C
Membrane: Operating System Support for Restartable File Systems Swaminathan Sundararaman, Sriram Subramanian, Abhishek Rajimwale, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau, Michael M. Swift Computer Sciences Department, University of Wisconsin, Madison Abstract and most complex code bases in the kernel. Further, We introduce Membrane, a set of changes to the oper- file systems are still under active development, and new ating system to support restartable file systems. Mem- ones are introduced quite frequently. For example, Linux brane allows an operating system to tolerate a broad has many established file systems, including ext2 [34], class of file system failures and does so while remain- ext3 [35], reiserfs [27], and still there is great interest in ing transparent to running applications; upon failure, the next-generation file systems such as Linux ext4 and btrfs. file system restarts, its state is restored, and pending ap- Thus, file systems are large, complex, and under develop- plication requests are serviced as if no failure had oc- ment, the perfect storm for numerous bugs to arise. curred. Membrane provides transparent recovery through Because of the likely presence of flaws in their imple- a lightweight logging and checkpoint infrastructure, and mentation, it is critical to consider how to recover from includes novel techniques to improve performance and file system crashes as well. Unfortunately, we cannot di- correctness of its fault-anticipation and recovery machin- rectly apply previous work from the device-driver litera- ery. We tested Membrane with ext2, ext3, and VFAT. ture to improving file-system fault recovery. File systems, Through experimentation, we show that Membrane in- unlike device drivers, are extremely stateful, as they man- duces little performance overhead and can tolerate a wide age vast amounts of both in-memory and persistent data; range of file system crashes. -
The Best of Both Worlds with On-Demand Virtualization
The Best of Both Worlds with On-Demand Virtualization Thawan Kooburat, Michael Swift University of Wisconsin-Madison [email protected], [email protected] Abstract Virtualization offers many benefits such as live migration, resource consolidation, and checkpointing. However, there are many cases where the overhead of virtualization is too high to justify for its merits. Most desktop and laptop PCs and many large web properties run natively because the benefits of virtualization are too small compared to the overhead. We propose a new middle ground: on-demand virtualization, in which systems run natively when they need native performance or features but can be converted on-the-fly to run virtually when necessary. This enables the user or system administrator to leverage the most useful features of virtualization, such as or checkpointing or consolidating workloads, during off-peak hours without paying the overhead during peak usage. We have developed a prototype of on-demand virtualization in Linux using the hibernate feature to transfer state between native execution and virtual execution, and find even networking applications can survive being virtualized. OS can return to native execution on its original hardware. 1. Introduction We call this approach on-demand virtualization, and it System virtualization offers many benefits in both data- gives operating systems an ability to be virtualized center and desktop environments, such as live migration, without service disruption. multi-tenancy, checkpointing, and the ability to run dif- Reaping the benefits of virtualization without its costs ferent operating systems at once. These features enable has been proposed previously in other forms. Microvisors hardware maintenance with little downtime, load ba- [14] provided the first step in the direction toward lancing for better throughput or power efficiency, and on-demand virtualization. -
Inside the Linux 2.6 Completely Fair Scheduler
Inside the Linux 2.6 Completely Fair Scheduler http://www.ibm.com/developerworks/library/l-completely-fair-scheduler/ developerWorks Technical topics Linux Technical library Inside the Linux 2.6 Completely Fair Scheduler Providing fair access to CPUs since 2.6.23 The task scheduler is a key part of any operating system, and Linux® continues to evolve and innovate in this area. In kernel 2.6.23, the Completely Fair Scheduler (CFS) was introduced. This scheduler, instead of relying on run queues, uses a red-black tree implementation for task management. Explore the ideas behind CFS, its implementation, and advantages over the prior O(1) scheduler. M. Tim Jones is an embedded firmware architect and the author of Artificial Intelligence: A Systems Approach, GNU/Linux Application Programming (now in its second edition), AI Application Programming (in its second edition), and BSD Sockets Programming from a Multilanguage Perspective. His engineering background ranges from the development of kernels for geosynchronous spacecraft to embedded systems architecture and networking protocols development. Tim is a Consultant Engineer for Emulex Corp. in Longmont, Colorado. 15 December 2009 Also available in Japanese The Linux scheduler is an interesting study in competing pressures. On one side are the use models in which Linux is applied. Although Linux was originally developed as a desktop operating system experiment, you'll now find it on servers, tiny embedded devices, mainframes, and supercomputers. Not surprisingly, the scheduling loads for these domains differ. On the other side are the technological advances made in the platform, including architectures (multiprocessing, symmetric multithreading, non-uniform memory access [NUMA]) and virtualization. -
Zack's Kernel News
KERNEL NEWS ZACK’S KERNEL NEWS ReiserFS Turmoil Their longer term plan, Alexander Multiport Card driver, again naming In light of recent events surrounding says, depends on what happens with himself the maintainer. Hans Reiser (http:// www. linux-maga- Hans. If Hans is released, the developers Jiri’s been submitting a number of zine. com/ issue/ 73/ Linux_World_News. intend to proceed as before. If he is not patches for these drivers, so it makes pdf), the question of how to continue released, Alexander’s best guess is that sense he would maintain them if he ReiserFS development came up on the the developers will try to appoint a wished; in any event, no other kernel linux-kernel mailing list. Alexander proxy to run Namesys. hacker has spoken up to claim the role. Lyamin from Hans’s Namesys company offered his take on the situation. He said Status of sysctl Filesystem Benchmarks that ReiserFS 3 has pretty much stabi- In keeping with Linus Torvalds’ recent Some early tests have indicated that ext4 lized into bugfix mode, though Suse assertions that it is never acceptable to is faster with disk writes than either ext3 folks had been adding new features like break user-space, Albert Cahalan volun- or Reiser4. There was general interest in ACL support. So ReiserFS 3 would go on teered to maintain the sysctl code if it these results, though the tests had some as before. couldn’t be removed. But Linus pointed problems (the tester thought delayed In terms of Reiser4, however, Alexan- out that really nothing actually used allocation was part of ext4, when that der said that he and the other Reiser de- sysctl (the implication being that it feature has not yet been merged into velopers were still addressing the techni- wouldn’t actually break anything to get Andrew Morton’s tree). -
Thread Scheduling in Multi-Core Operating Systems Redha Gouicem
Thread Scheduling in Multi-core Operating Systems Redha Gouicem To cite this version: Redha Gouicem. Thread Scheduling in Multi-core Operating Systems. Computer Science [cs]. Sor- bonne Université, 2020. English. tel-02977242 HAL Id: tel-02977242 https://hal.archives-ouvertes.fr/tel-02977242 Submitted on 24 Oct 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Ph.D thesis in Computer Science Thread Scheduling in Multi-core Operating Systems How to Understand, Improve and Fix your Scheduler Redha GOUICEM Sorbonne Université Laboratoire d’Informatique de Paris 6 Inria Whisper Team PH.D.DEFENSE: 23 October 2020, Paris, France JURYMEMBERS: Mr. Pascal Felber, Full Professor, Université de Neuchâtel Reviewer Mr. Vivien Quéma, Full Professor, Grenoble INP (ENSIMAG) Reviewer Mr. Rachid Guerraoui, Full Professor, École Polytechnique Fédérale de Lausanne Examiner Ms. Karine Heydemann, Associate Professor, Sorbonne Université Examiner Mr. Etienne Rivière, Full Professor, University of Louvain Examiner Mr. Gilles Muller, Senior Research Scientist, Inria Advisor Mr. Julien Sopena, Associate Professor, Sorbonne Université Advisor ABSTRACT In this thesis, we address the problem of schedulers for multi-core architectures from several perspectives: design (simplicity and correct- ness), performance improvement and the development of application- specific schedulers. -
Package Manager: the Core of a GNU/Linux Distribution
Package Manager: The Core of a GNU/Linux Distribution by Andrey Falko A Thesis submitted to the Faculty in partial fulfillment of the requirements for the BACHELOR OF ARTS Accepted Paul Shields, Thesis Adviser Allen Altman, Second Reader Christopher K. Callanan, Third Reader Mary B. Marcy, Provost and Vice President Simon’s Rock College Great Barrington, Massachusetts 2007 Abstract Package Manager: The Core of a GNU/Linux Distribution by Andrey Falko As GNU/Linux operating systems have been growing in popularity, their size has also been growing. To deal with this growth people created special programs to organize the software available for GNU/Linux users. These programs are called package managers. There exists a very wide variety of package managers, all offering their own benefits and deficiencies. This thesis explores all of the major aspects of package management in the GNU/Linux world. It covers what it is like to work without package managers, primitive package man- agement techniques, and modern package management schemes. The thesis presents the creation of a package manager called Vestigium. The creation of Vestigium is an attempt to automate the handling of file collisions between packages, provide a seamless interface for installing both binary packages and packages built from source, and to allow per package optimization capabilities. Some of the features Vestigium is built to have are lacking in current package managers. No current package manager contains all the features which Vestigium is built to have. Additionally, the thesis explains the problems that developers face in maintaining their respective package managers. i Acknowledgments I thank my thesis committee members, Paul Shields, Chris Callanan, and Allen Altman for being patient with my error-ridden drafts. -
Machine Learning for Load Balancing in the Linux Kernel Jingde Chen Subho S
Machine Learning for Load Balancing in the Linux Kernel Jingde Chen Subho S. Banerjee [email protected] [email protected] University of Illinois at Urbana-Champaign University of Illinois at Urbana-Champaign Zbigniew T. Kalbarczyk Ravishankar K. Iyer [email protected] [email protected] University of Illinois at Urbana-Champaign University of Illinois at Urbana-Champaign Abstract ACM Reference Format: The OS load balancing algorithm governs the performance Jingde Chen, Subho S. Banerjee, Zbigniew T. Kalbarczyk, and Rav- gains provided by a multiprocessor computer system. The ishankar K. Iyer. 2020. Machine Learning for Load Balancing in Linux’s Completely Fair Scheduler (CFS) scheduler tracks the Linux Kernel. In 11th ACM SIGOPS Asia-Pacific Workshop on Systems (APSys ’20), August 24–25, 2020, Tsukuba, Japan. ACM, New process loads by average CPU utilization to balance work- York, NY, USA, 8 pages. https://doi.org/10.1145/3409963.3410492 load between processor cores. That approach maximizes the utilization of processing time but overlooks the con- tention for lower-level hardware resources. In servers run- 1 Introduction ning compute-intensive workloads, an imbalanced need for The Linux scheduler, called the Completely Fair Scheduler limited computing resources hinders execution performance. (CFS) algorithm, enforces a fair scheduling policy that aims to This paper solves the above problem using a machine learn- allow all tasks to be executed with a fair quota of processing ing (ML)-based resource-aware load balancer. We describe time. CFS allocates CPU time appropriately among the avail- (1) low-overhead methods for collecting training data; (2) an able hardware threads to allow processes to make forward ML model based on a multi-layer perceptron model that imi- progress. -
Weekend Chat
COMMUNITY FOSDEM 2004 FOSDEM 2004 Weekend Chat FOSDEM is the Free and Open Source Developers Meeting that takes place each year in Belgium’s capital city of Brussels.The meeting can be split into two halves. BY JOHN SOUTHERN Figure 2: Jon “Maddog” Hall explaining history. he first half is the organized talks, Love, who talked about the kernel and Talking lectures and tutorials which take its affects on the desktop. Followed by The second half of FOSDEM is just as Tplace over a weekend, This year 2.6 Internals and then Hans Reiser took important. It is the community activities. started with an opening speech by Tim listeners on a tour of Reiser 4. Those that can spare the Friday evening, O’Reilly of O’Reilly books. Everyone lis- In the tutorials, scripting languages meet in the Roy d’Espagne for an tens to the opening speech and the included Ruby and NetBeans. Everyone evening of Belgian beer. traditional talk by Richard Stallman. then met for the Free Software Award, Although the beer is wonderful, many RMS gave his traditional speech, which was won by Alan Cox, and the do not drink and still go because this is including his Saint IGNUcius sketch, singing of the Free Software song. where you meet up others and get a where he blesses the crowd and indoc- Sunday started with streams on X and chance to chat about what everyone torates them in the Church of Emacs. Java. In the tutorial room, rather than thinks are the important developments. hour long talks, we were treated to sev- This chatting to like minded strangers, Talks enteen short fifteen minute talks.