The Linux Foundation has put out a fascinating study on Linux kernel development, who’s doing it and how fast things are moving. In reading through the report, I’ve picked out some of the statistics and points that stood out to me:

There have been almost 10,000 patches in each recent ~quarterly Linux kernel release. Releases include work from ~1,000 developers and ~100 companies. Since 2005, Linux has had more than 3,600 individual developers and more than 250 companies contributing to the kernel.

The individual development community has tripled in the last three years. The top 10 developers have contributed 15% of changes, and the top 30 developers have contributed 30% of changes to the kernel.

Linus Torvalds is 27th on the list of contributors with most changes over the last few years. He has 495 to his name. The list is led by Al Viro, with 1,571 changes, David S. Miller with 1,520 changes and Adrian Bunk with 1,441 changes. Andrew Morton is fifth with 1,222 changes and Greg Kroah-Hartman, co-author of the report, just edged out Linus to rank 26th in contributed changes at 496.

In terms of the companies contributing to Linux, the bulk of contributions come not from any individual companies, but in true Linux and open source fashion from community developers. More than 11,500 or 14% of kernel changes have come from developers with no commercial entity backing their Linux development. Another 13% of changes come from developers with ‘unknown’ commercial affiliation. When we get to actual companies, Red Hat leads with 9,351 kernel changes, or 11.2%. Next is Novell with 8.9%, IBM with 8.3% and Intel with 4.1% of kernel changes. Others with more than 1% of contributed kernel changes include: Linux Foundation, SGI, MIPS Technologies, Oracle and MontaVista.

As further evidence of increasing commercial support and contribution to Linux, the report authors said despite the large number of kernel changes coming from those with no or unknown commercial affiliation, more than 70% of all kernel development is demonstrably done by developers who are being paid for their work.

From the 2.6.11 kernel to the 2.6.24 release (1,140 days), there were an average of 2.8 accepted patches applied to the Linux kernel tree per hour. An average of more than 3,600 lines of code is added to the Linux kernel tree every day. Since 2005, the kernel has grown at a steady rate of 10% per year.

The Linux Foundation, which rightly points out that vendor participation is strategic and competitive rather than charitable, concludes that current work on server, desktop and embedded Linux should sustain the growth of Linux development. The latest Linux Foundation study serves as a good measure of where the OS is today and how it is progressing. It also highlights why Linux remains a shining example of how open source software development is supposed to work.