Linux contributor base broadens
In the latest kernel release, the most active 30 developers authored only 30% of the changes, while two years ago, the top 20 developers did 80% of the changes, he said. Kroah-Hartman himself is now doing more code reviewing than coding. "That's all I do, is read patches these days," he said.
In theory, the kernel development process would involve changes, or patches, moving from the original author through a file or driver maintainer, to the maintainer of a major subsystem such as PCI or SCSI, to Andrew Morton for testing and finally to Linus Torvalds for a kernel release. But, Kroah-Hartman said, "I tried graphing that. That's not what happens. It's a mess. There's routing all over the place."
A graph of all the developers involved in the upcoming 2.6.22 release, and the relationships of who reviewed whose patches, extends to a 40-foot-long printout with names in tiny type. The graph is on display at the Ottawa event.
The opening day of the 9th annual Ottawa Linux Symposium (OLS) began with Jonathan Corbet, of Linux Weekly News and his now familiar annual Linux Kernel Report, and wrapped up with a reception put on by Intel where they displayed hardware prototypes for upcoming products.
The Kernel Report
Corbet's opening keynote began with a very brief history of Linux, showing the kernel release cycle since it was started in 1991. He made the point that the kernel has gone from a significant release every couple of years to one every couple of months over the last few years, with every point release of the kernel being a major release. Today, every point release has new features and API changes.
The release cycle today is very predictable, says Corbet, with kernel 2.6.22 anticipated in July and 2.6.23 expected around October. The cycle starts with a kernel, say 2.6.22-rc1, then a second release candidate is made available, and a third (if necessary), and so on until the release candidate becomes stable, and work begins on the next kernel.