Highlights from Linux Kongress

The 13th annual International Linux System Technology Conference, also known as Linux Kongress, took place September 5 - 8 in Nürnberg, Germany. As a technical Linux event Linux Kongress is smaller in scale than the Ottawa Linux Symposium and linux.conf.au. Still the conference sessions and tutorials included a number of quality talks from familiar members of the Linux and open source communities such as Heinz Mauelshagen, Lars Mueller, Theodore Ts'o, Volker Lendecke, Alan Robertson, and Daniel Phillips.

A few of the talks stood out. One such talk was Felix von Leitner's presentation titled "Benchmarking, round 2: I/O Performance", in which he tested file system performance on Linux, Windows, OpenSolaris, NetBSD, FreeBSD, and OpenBSD in order to better understand the scalability of different operating systems and IP stack throughput. Based on von Leitner's benchmarking methodology Linux has the fastest file system - reiser4.

The testing theme continued with Poornima Bangalore, whose presentation was on the topic of "Best Practices in Linux Kernel Testing." Her talk detailed many of the key differences between traditional and open source testing. She pointed out that mainline kernel testing is more challenging than testing many other open source projects because of the rapid development and the different sub trees in the kernel: the stable kernels are released every 6 weeks or so, release candidate (-rc) kernels are available every week, and experimental (-mm) kernels are available every few days. Poornima shared best practices regarding kernel configuration, hardware configuration, test automation, test coverage, and first failure data capture.

Heinz Mauelshagen gave a talk on device-mapper architecture features and the related target feature set. In the talk "Linux as a Hypervisor," Jeff Dike discussed the evolution of the hypervisor support in the Linux kernel and how capabilities such as ptrace, AIO and O_DIRECT make a difference to virtual machines. He also talked about the implications of FUSE (filesystems in userspace) and the manageability benefits of exporting a UML filesystem to the host. Lars Marowsky-Bree's presentation on Heartbeat 2 and Xen explored Heartbeat's ability to manage Xen guests. He expanded on Heartbeat's architecture and its integration with Xen to enable resource reallocation, globally ordered recovery actions, and data center automation policies using the Cluster Resource Manager (CRM).

Mattias Rechenburg's presentation on "Using Enterprise Data Centers with OpenQRM" showcased the state of OpenQRM an open source project to achieve high-availability, scalability, and deployment, service and server virtualization on a variety of operation system. In spite of OpenQRM's pluggable architecture, the audience focused on the fact that it depends on a binary module which requires support from Qlusters. The general sentiment from the audience was they were not interested if they couldn't get support from Red Hat, IBM, Hewlett-Packard etc.

In "Real-Time Approaches to Linux," Ted Ts'o shared his perspective on enterprise real-time computing and how it differs from so-called traditional real-time computing. He emphasized the changing requirements in enterprise software and how high throughput is not enough because customers increasingly also require latency guarantees, especially in particular military applications and trading systems. It was interesting to hear about the benefits and tradeoffs of different approaches to enterprise real-time including RTAI and Ingo Molnar's CONFIG_PREEMPT_RT.

Ted suggested that guidelines outlined by his colleague Paul McKenney can be used to evaluate the different approaches to enterprise real-time. This includes quality of service, the amount of code inspection required when a new feature is added, the API provided to applications, the relative complexity, fault isolation, and supported hardware and software configurations.

Although IBM presently has only one customer that plans to deploy enterprise real-time computing, the ability to support large SMP systems, TCP/IP, commercially available middleware, and databases makes it an area to watch in the future. Ted also elaborated on the features of IBM's real-time JVM/SDK (aka IBM Websphere Real-Time v1.0) such as RTSJ (Real-time specification for Java), the Metronome real-time garbage collector, and AOT (Ahead of Time Compilation). The talk emphasized that there are many new applications for real-time operating systems, and in particular enterprise real-time Linux.

Maddog provided the final keynote on having fun with open source in his own inimitable way.