FreeBSD Foundation Newsletter, August 9, 2011
In this Edition:
- Letter From the President
- Fundraising Update
- Development Project Updates
- IPv6 support in FreeBSD and PC-BSD
- Implementing support of GEM, KMS, and DRI for Intel Drivers
- Resource Containers Project
- Feed-Forward Clock Synchronization Algorithms Project
- Five New TCP Project
- libcxxrt C++ Runtime Available Under BSD License
- Conference Updates
- 2011 Grant and Travel Grant Recipients
- NYI Testimonial
- Foundation Update
As a software architect, I'm constantly asked to scope new features or projects, and to estimate the cost to complete them. Without doing all the work up front, making accurate estimates is hard, but in most cases it is possible to come up with a number that differs at most 20% from the accounted cost at the end of a project. But there have been many times I've fallen far from that mark. The biggest culprit of these errors for me has been in assuming that a stated feature of a component I plan to rely on operates as advertised.
The classic approach to improving estimates is to perform sufficient exploratory testing and prototyping to reduce risk. But when your product includes an OS (or three, as is the case with the product I work on for Spectra Logic) and software from dozens of third parties, you simply don't have time to test everything in advance. Based on past experience you must identify those components you believe have the highest chance of failure, test them, and hope the others don't burn you later in the development cycle.
When dealing with Open Source components, how do you estimate this risk? You can explore the online community surrounding that software in search of trouble spots. A survey of the revision control history and source code may give an indication of how well it is designed. If you've already used the software before, that may also give you confidence that it will work again. Unfortunately, none of these strategies are a true replacement for testing.
"Even for a component I've used before?" you ask? The problem with new product development is that you rarely use the exact version of the exact same software in exactly the same way as you did in the past. Software that you've used and tested certainly has lower risk than something completely untested. But the more complicated the software or the product you are trying to build, the greater the chance that a previously undetected defect or regression will rear its head.
Let me site a concrete example from my own work on a FreeBSD based disk product. Like all disk systems that offer some redundancy, disk soft and hard errors must be tested. Our test suite passed with flying colors early in our development phase, but that was not our experience after bringing in what appeared to be a set of benign updates from the FreeBSD stable branch. Pulling a disk from our array almost always resulted in a deadlock. With a FreeBSD revision just a few months newer, the problem went away.
The amazing thing we learned after tracking down the root cause of this failure was that both those who introduced the problem and those who resolved it, were completely unaware that the problem existed. The innocent introduction of some sysctl nodes in the FreeBSD disk driver caused a deadlock with the GEOM layer's topology reporting code. If both a topology request and disk departure happened to coincide, deadlock. The fix, decoupling sysctl requests from sysctl node removal, was made for unrelated reasons. In complex software systems, the connections between components can be hard to visualize, making the true risk of a change almost impossible to estimate.
So if testing is the only solution, how can an integrator of Open Source software mitigate risk without devoting a large percentage of their resources to testing? There are two answers to this question: develop an automated test suite that streamlines your validation procedures, or choose components from Open Source projects that already perform this kind of testing. Only by building up a large body of tests and augmenting it whenever a defect slips through, can you manage the risk inherent to complex software systems.
Since its inception, FreeBSD has promoted the best practices of software development. However, we seem to have missed the trend toward "Test Driven Development" of software. Code reviews, tools like witness, strategic placement of invariant checks within the code, and the amazing exploratory testing efforts of members of our community like Peter Holm have made FreeBSD very reliable. But they do not guard against regressions or provide the same confidence of correctness as a high quality suite of automated tests.
Talking with others at the vendor summit during this year's BSDCan, it's clear that many FreeBSD consumers already rely on automated testing to prove correctness of their products. Some of these test suites likely validate generic FreeBSD functionality, but there is currently no shared testing framework in FreeBSD that would allow both the shared burden of test development, and the shared benefit of having FreeBSD defects detected by our community within hours of their introduction. Transitioning FreeBSD to a test driven methodology would dramatically increase the value proposition of our OS.
How do we get there? Others have shown the way forward: the Automated Test Framework and userspace kernel support found in NetBSD, hooks for trapping device driver accesses developed for Linux in 2003, and a vast body of literature on test driven methodologies. The FreeBSD Foundation stands ready to provide the resources needed to start this transition for FreeBSD. If you are interested in working on a unified test framework for FreeBSD, or developing tests for subsystems in FreeBSD, please consider sending us a grant proposal.
Justin T. Gibbs
President and Founder
The FreeBSD Foundation
We are so thankful of the support we receive from so many individuals and companies who value FreeBSD. As of this publication, we have raised $153,000 towards our annual fund raising goal of $400,000. This is a tremendous improvement over last year, where we had only met 15% of our goal by the mid-year mark! We're optimistic about hitting our donation target in the remaining 5 months of the year, but, we do have a lot of work ahead of us to reach this goal!
In this newsletter we have highlighted many aspects of the FreeBSD Foundation's work, including funded development projects, sponsorship of conferences and developer travel, and investments in project infrastructure. These articles begin to paint a picture of how support for the FreeBSD Foundation, translates into support for FreeBSD. But many of our activities are less visible.
- Investing in the FreeBSD Foundation provides protection to the Project's logo, trademarks, and other intellectual property.
- Investing in the FreeBSD Foundation allows us to create and license critical software infrastructure under the BSD license.
- Investing in the FreeBSD Foundation gives the FreeBSD Project access to legal advice.
These are just a few examples of how we spend our money. Know that donating to the FreeBSD Foundation is the most cost effective way you can ensure the future of FreeBSD. With your help, we look forward to not only meeting our fundraising goal, but increasing our investment in FreeBSD for 2012 and beyond!
The Internet Protocol version 6 (IPv6) is the next generation Internet Protocol. FreeBSD has supported IPv6 as an optionally configured feature since the 4.0 release with the KAME-based reference implementation.
With this work on the IPv6-only kernel, FreeBSD can now run IPv6 without the need for the formerly implied dependency on IPv4. Taking this exciting work from a research project, to being available in FreeBSD 9.0, will allow further IPv6-only validation work to happen; not only for FreeBSD, but also for other open source, commercial, and research software.
Having an IPv6-only desktop system with PC-BSD and the IPv6-only server platform with FreeBSD will facilitate finding bugs, invalid or confusing error messages, and broken or nonexistent IPv6 support in the system. Many of these faults would otherwise go unnoticed due to the previous fallback on IPv4 networking. In the long term, this will improve the overall maturity of the IPv6 implementation of FreeBSD and motivate other folks throughout the industry to improve their applications for IPv6-readiness.
I'd like to thank the FreeBSD Foundation and iXsystems for sponsoring this project, and foreseeing the importance of IPv6 in the coming years.
contributed by Björn Zeeb
I have used FreeBSD as my primary desktop for more then 10 years. Recently, I noticed that the future of FreeBSD on the desktop seemed dim, even for devoted users such as myself. The reason is the lack of support for off-the-shelf GPUs in my beloved OS. Although my Sony VAIO Z820 works perfectly with UMS and DRI1 drivers, the next generation of the Intel platform can only work with the VESA driver. Systems based on this technology have slow graphics performance and often fail to use the native resolution of LCD panels, not to mention have no support for hardware-accelerated 2D or OpenGL. Can you say, "DRI1 interfaces are messy?"
Despite the Xorg crowd ignoring everything but Linux, the only really hard part of getting Intel graphics running on FreeBSD is getting the kernel bits in place. The Intel kernel driver consists of two relatively independent parts. The first is GEM: a manager of GPU memory, or rather remapping of system RAM into the GPU address space, and directing command execution. GEM ensures that the CPU and GPU have a consistent view of the memory, taking care of non-coherent caches.
The second part is mode-setting, which provides a way to enumerate the connectors, get the capabilities of the monitors attached to them, and properly configure the transmitters to drive the video and audio streams.
Knowing a little about our virtual memory subsystem, I considered porting GEM for some time before the Foundation-sponsored project started. But, the amount of required work and commitment of time needed to port ~20KLOC of code put a bar on the work. In the end, I spent 5 months porting and debugging GEM and KMS to get it to the state where the X server can be started. Without the support of the FreeBSD Foundation, I would not have been able to perform the porting.
An interesting experience during this time was the constant flood of emails with proposals to 'test' the code. I anticipated that people would like to get 'early' access to the unwritten code, but there were so many requests that I felt it was more important for me to spend my time on the work rather than spending it responding to emails.
On my Core i5 600, I have kernel-modesetting working over the HDMI-connected monitor. The ever-important ioquake3 and uhexen2, as well as mplayer, also work. I expect to have a patch suitable for wider public testing by mid-August. I believe that several more months will be required after that date to have a relatively stable driver, ready for general public use.
Anyway, a lot of work still needs to be done to make the driver ready for everyday use, but at least now I know which kind of platforms to look for when buying a new laptop.
contributed by Kostik Belousov
The goal of the RCTL project, previously known as Resource Containers, was to provide system administrators with a mechanism to limit per-jail resource consumption. In the end, it turned out to be much more than that: it allows system administrators to query current resource usage, and to manipulate rules describing per-user, per-login class, and per-jail resource limits. RCTL allows system administrators to choose various actions when resource limits are reached - it can not only just deny the allocation, but also send a signal (e.g. killing the offending process), log a warning to the syslog, or even trigger a devd(8) action that restarts a problematic daemon or jail. In this regard, it's somewhat similar to Solaris resource management (prctl(1) et al).
In addition to the core functionality, the concept of login class has been added to the kernel. Previously, login classes existed only in userspace and were used, among other things, to set traditional UNIX per-process resource limits (setrlimit(2)) during login. Now, the kernel is aware of the login class of the process; this makes it possible to limit resource usage for the whole login classes, not just for individual processes or users assigned to that login class. This makes login classes somewhat similar in purpose to Solaris projects.
Almost all of the code has already been merged into CURRENT and will appear in 9.0-RELEASE. In order to use it, the kernel needs to be rebuilt with "options RACCT" and "options RCTL." Remaining work, in particular adding %CPU and I/O rate limiting, probably won't be ready for 9.0.
contributed by Edward Tomasz Napierała
For many years, the ntpd synchronization daemon and the Network Time Protocol (NTP) have been the reference solution to synchronize computer clocks inexpensively on FreeBSD. Today, applications need access to more and more accurate, but also reliable, time. The ntpd daemon has shown its limits, with complex code, performance ranging from very good to very bad, and no objective bound on its clock error. The instability of ntpd is mainly due to the feed-back nature of its interaction with the kernel: inaccurate timestamps created by the system clock are fed to the ntpd daemon and lead to potentially erratic clock error.
Because it does not couple kernel and synchronisation daemon time, a feed-forward approach is inherently robust and allows near-optimal performance to be reached. This project aims at extending the FreeBSD kernel timing system to support feed-forward synchronisation daemons such as the RADclock. This new synchronisation system will allow both feed-back and feed-forward approaches to run on one system and give users the possibility to select the one more suited to their needs.
In addition, the feed-forward approach provides various new features such as faster timestamping, a new difference clock to measure time intervals with GPS-like accuracy and extremely high robustness, useful specialised flavours of "wall-clock" time, an ability to `replay' the clock offline based on stored raw timestamps (counter values), and accurate timing for virtual machines and live VM migration.
The FreeBSD Foundation is sponsoring Julien Ridoux and Darryl Veitch at the University of Melbourne to bring the feed-forward support to FreeBSD. The project is nearing completion and the code should be available for testing by August 2011.
contributed by Julien Ridoux and Darryl Veitch
TCP is a crucial part of any modern operating system. FreeBSD's standard "NewReno" congestion control (CC) is not able to fully utilize the high capacity links available today. A range of newer CC algorithms have emerged (and continue to emerge) from the networking research community over the past 15+ years. These include traditional loss-based algorithms (where packet losses indicate network congestion) and delay-based algorithms (where changes in Round Trip Time, RTT, are used to infer network congestion).
However, to date FreeBSD's TCP stack has not had an easy-to-use mechanism for introducing new CC algorithms. In recent years the Centre for Advanced Internet Architectures (CAIA) at Swinburne University of Technology has (with the support of the Cisco University Research Program Fund at Community Foundation Silicon Valley) been developing a range of extensions to the FreeBSD TCP stack. These included a modular framework for adding new CC algorithms and new modular implementations of the existing NewReno algorithm, four other algorithms from the literature (H-TCP, CUBIC, Vegas and HD) and a novel algorithm developed at CAIA (CHD). In mid-2010 the FreeBSD Foundation funded CAIA to complete, tidy up and commit a number of these key enhancements to the FreeBSD TCP stack. Click here to read more
contributed by Grenville Armitage
The FreeBSD Foundation and the NetBSD Foundation have acquired a non-exclusive copyright license to the libcxxrt C++ runtime software from PathScale, a leader in high performance Fortran, C and C++ compiler products for AMD64, Intel64 and MIPS. This software is an implementation of the C++ Application Binary Interface originally developed for Itanium and now used for the x86 family by BSD operating systems. Libcxxrt will be available under the 2-clause BSD license.
This implementation is a full replacement for the GNU libsupc++ library for platforms that use the Itanium C++ ABI, including i386 and x86-64, and will replace portions of the C++ stack previously only available under the GPL. It provides implementations of the dynamic features of C++, including dynamic casting, exception handling, and thread-safe static initializers, and will continue the gradual replacement of GNU toolchain and runtime components, furthering the aim of a purely BSD-licensed system.
"This work complements other work done in the community and is a further step in letting us adopt alternative toolchains in FreeBSD," said Robert Watson, a FreeBSD committer and Director at the FreeBSD Foundation.
"There are already a number of STL implementations with other licenses, but libcxxrt is the missing link for a BSD licensed C++ compiler and the C++ runtime," said NetBSD developer Joerg Sonnenberger.
"It's great to work with the BSD community and help provide these core parts of the toolchain," said Christopher Bergström, CTO at PathScale. "This is a first step to PathScale offering first class support for both NetBSD and FreeBSD."
AsiaBSDCon is an international conference for users and developers on BSD-derived operating systems. This conference started in 2004, and it has been held in Japan on a yearly basis since 2007. It consists of tutorials, paper sessions, small meetings, and a banquet.
The primary goal of AsiaBSDCon is to collect the best technical papers and presentations available to ensure that the latest developments in our open source community are shared with the widest possible audience. The average number of attendees for this conference is 100, and the number of tutorials and papers are 4 and 16 every year, respectively. The official language is English. In general, a talk in the conference has a paper corresponding to it, and a printed proceedings which contains all of the papers is distributed in advance, as is the common practice in academia, to help people understand the topics.How does FreeBSD benefit from AsiaBSDCon?
A lot of FreeBSD developers attended AsiaBSDCon and actively discussed their on-going projects. Over 20 technical papers on FreeBSD and/or by active FreeBSD developers were presented. The papers in PDF and videos of them can be found at the official web site.
Although we already have several long-established BSD conferences including BSDCan in Canada and EuroBSDCon in the European region, few people living in Asian countries attend them because of the distance, cost, and language issue. While many developers in the Asian region are not so visible for this reason, they have worked on interesting problems due to unique characteristics in terms of information technology such as internationalization and IPv6 by using FreeBSD. BSD developers from all over Asia, Europe, and North America attend every year. One of the goals of AsiaBSDCon is to provide an opportunity for face-to-face communication among such people, and it has been successful so far.
This conference has roughly been recognized as "an annual BSD conference in Japan" and a good place to mingle with such Asian developers. Tokyo is also an attractive tourist destination; excellent Japanese food, high-speed Internet access, Akihabara Electric Town for digital gadget geeks---a mixture of Eastern traditional culture and advanced technology.Sponsorship
AsiaBSDCon has been fortunate to be sponsored by several organizations. The FreeBSD Foundation is one of the primary sponsors of AsiaBSDCon for many years. Internet Initiative Japan, S2 Factory, iXsystems, USENIX, and Sakura Internet have been supporting us for a long time.
A rough breakdown of the budget is the following: 50% for speakers' travel expenses, 25% for venue and meals, and another 25% for proceedings and goods. Our income from the sponsorship covers around 70% of the whole budget every year.AsiaBSDCon 2011 and March 11th Earthquake
In the afternoon on March 11, 2011 a big earthquake hit the northern area of Japan. As reported worldwide, a tsunami caused by it struck Fukushima Prefecture and, as of July, the death toll reached over 15,000. Although Japan is well known for its earthquakes, the damage caused by this one was well beyond the imaginations of the Japanese people. Below is a story of AsiaBSDCon 2011 from the chairperson's perspective.
AsiaBSDCon 2011 was planned to be held March 17-20. The earthquake hit just one week before. The venue was in central Tokyo and damage around that area was quite small---this was probably contrary to all expectations. The earthquake was big, but the magnitude was not one that made the average Japanese panic immediately. I was in my office at that time and felt the shock, neither my office, building, nor road around had collapsed. While some of the public transportation facilities in Tokyo area became suspended for a while, because it needed to be checked for possible trouble, there was no other serious damage than that in the area. The primary trouble at that time was traffic congestion due to the suspension and difficulty in returning home. Actually I had to stay in my office the whole day. One positive piece of news was that there weren't any BSD community members who were victims of the earthquake and tsunami.
It was a difficult decision to go ahead with the conference, but with the small amount of damage in Tokyo, we decided to go ahead as planned. The on-line registration was almost closed, and preparation of the printed proceedings was already done. We reached the point of no return regarding these preparations.
I contacted the speakers and most of them let us know their plans had not changed. However, three days after the decision, we received a report on the problems with the Fukushima nuclear power plant and the possibility of rolling blackouts. Most of speakers were not able to come to Japan because of strong travel warnings from their governments, organizations, and/or families. I could totally understand their concerns. What I could do at that time was to gather more information about the on-going situation.
Three days before the conference, I received notice from several of the speakers that they could not come to Japan, because of the uncertainty about the safety. Some of them had landed already, but still had to return home.
I reorganized the conference schedule and decided to cancel all of the tutorials. I started to experiment with different video conferencing software because some of the speakers who couldn't attend, offered their talks via video conferencing. It was certainly an attractive option for us, but I was not sure how well it would work. We only had 48 hours to go. What software should we use? What was the best option for their time differences as well as our time table? It was a very busy day.
At the conference, we had one keynote speech and seven talks. For FreeBSD-related topics, PC-BSD's PBI package management by Kris Moore, system management with ZFS by Brooks Davis, Lua scripting by Ivan Voras, and PTPd time synchronizing system by George Neville-Neil were presented. There were around 60 attendees and 10% came from overseas. Although we had to cancel most of talks, and had a smaller number of attendees than usual, we still enjoyed meeting face-to-face.
I would like to give a big "thank you" to all of the attendees and people who supported AsiaBSDCon this year.Future Conferences
The situation now in Japan is far better than it was in March, so we're moving forward and preparing for AsiaBSDCon 2012. Please consider submitting your paper and coming to Japan. If you are worried about difficulties with the language don't worry, especially if you aren't having a problem reading this article. Japan is filled with English signage and the organizing staff is here to help. We are sure you will have a wonderful experience here!
Official web site: http://asiabsdcon.org/ Contact: email@example.com
contributed by Hiroki Sato
BSDCan is a technical conference for people working on, and with, 4.4BSD based operating systems and related projects. Since our start in 2004, we have kept the conference format simple, and have adhered to the core conference functions. We believe the primary purpose of a conference is to meet, learn, and discuss. We believe that good relationships go a long way towards cooperation within, and between, projects. With this in mind, we try to maximize the opportunities for attendees to meet their peers, and discuss their work and interests. To give people plenty of time to talk and mingle, most sessions have a 30 minute break after each talk. This break also benefits the speaker, so they have plenty of time to setup. We also provide lunch at the venue because we feel that this time fosters even more discussions.
Since the start, BSDCan has provided a venue for all projects to gather, talk about their projects, collaborate on work, and make plans for future work. Each year, after the conference, we see references such as "as discussed at BSDCan," or "based on work presented at BSDCan." It gives us much satisfaction that we can contribute in this way.
Conferences are expensive to attend. Travel and accommodation costs are way up there. While we strive to keep registration costs down for the attendee, there is nothing we can do about travel costs. Not all speakers can pay their own way to conferences. For those that cannot, we try to help. The grants from the FreeBSD Foundation go a long way to ensuring that we can help.
BSDCan has helped organize a FreeBSD Dev Summit for several years; getting larger every year. It is clearly a popular feature of the conference. At BSDCan 2011, we had a new track: Public FreeBSD Dev Summit.
One of the most memorable moments at BSDCan 2011 happened after one of the sessions. I witnessed many developers from several projects standing at the front of the hall. They were talking about common code, and how to better coordinate their work. I overheard them making plans for improvement. This wasn't a first, but it is definitely something that seems to happen more readily in person, than on mailing lists.
BSDCan is proud that its actions can contribute to all projects and hope this continues in the years to come.
contributed by Dan Langille
Every year we sponsor FreeBSD related conferences, projects, and developer travel. We believe that BSD-centered and FreeBSD-specific conferences play critical roles in expanding the FreeBSD user community and supporting collaborative development. Our grants may be for something as little as performance software to large projects like Network Stack Virtualization.
To find out how to apply for a travel grant, please visit http://www.freebsdfoundation.org/documents/TravelRequestForm.pdf. To get information on how to apply for a grant, please visit http://www.freebsdfoundation.org/documents/GrantRequestForm.pdf.
Here is a list of projects, developers, and conferences we have sponsored for 2011.
2011 Conference Grant Recipients:
- AsiaBSDCon 2011 Conference
- BSDCan 2011 Conference
- EuroBSDCon 2011 Conference
2011 Project Grant Recipients:
- Swinburne University - Five New TCP Congestion Control Algorithms Project
- Edward Tomasz Napierala - Resource Containers
- Konstantin Bilousov - GEM, KMS, and DRI for Intel Drivers
- Bjoern Zeeb - IPv6 Day Project
- University of Melbourne - Feed-Forward Clock Synchronization Algorithms Project
2011 Travel Grant Recipients:
- FOSDEM - Brooks Davis
- BSDCan - Thomas Abthorpe, Sergio Ligregni, Simon Nielson, Julien Laffaye, Daichi Goto, Attilio Rao
- Other - Mark Linimon
NYI is a data center provider that uses FreeBSD for all of its internal and customer-facing solutions for colocation and dedicated servers, cloud computing and managed services. Our initial choice of technology included commercial Unix systems tied to proprietary hardware. However, the cost and portability of FreeBSD were determining factors in our changing platforms early in our company's existence.
Since then, we have enjoyed the functionality and reliability of FreeBSD. We rely on it for networking duties like routers, VPNs, firewalls and traffic shapers, as well as web applications like shared hosting, backend interfaces, load balancers and proxies. We particularly appreciate the community support and centralized documentation, which means that we do not have to hunt down bits and pieces of information, like we would with other projects.-Phillip Koblence, VP Operations, NYI, www.nyi.net
We're pleased announce the addition of Ed Maste to our Board of Directors. Ed has been involved with FreeBSD since 2003. And, has been a committer since 2005. Ed leads the OS team at Sandvine and is responsible for a number of developers who bring enhancements from FreeBSD into Sandvine's OS and contribute their own changes back to FreeBSD.
Ed replaces Paul Saab as a director on the board. Paul had been with the foundation since 2007. We would like to thank Paul for all of his contributions to the foundation and Project over the four years he was on our board.