A Linux Foundation report found that among the growing list of companies participating in Linux kernel development, embedded-oriented firms like Linaro, Samsung, and Texas Instruments, have increased their contributions at the fastest rate. Other findings include increases in the number of kernel developers, code changes, and changes per hour since the LF’s previous report in April 2012.

The Linux Foundation’s 2013 kernel report, called “Linux Kernel Development: How Fast It is Going, Who is Doing It, What They Are Doing and Who is Sponsoring It,” is the non-profit Linux advocacy organization’s fifth such report released on a roughly annual basis. The report on “the largest collaborative project in the history of computing,” covers Linux 3.0 through the latest 3.10 kernel, with an emphasis on 3.3 to 3.10. The previous April 2012 report surveyed Linux 2.6.36 through 3.2.

The LF’s Linux Kernel Development report was released on the first day of the organization’s LinuxCon North America conference in New Orleans, as well as a concurrent CloudOpen conference. Since its inception four years ago, the fast-growing LinuxCon conference has played primarily to the enterprise server and cloud development audience, and that continues here. (Embedded Linux geeks are instead directed to the Embedded Linux Conference.)

Yet, embedded has been playing a growing role at mainstream Linux conferences like LinuxCon. This year’s show has a surprising amount of embedded-oriented speakers and presentations, as we noted in our July analysis of the LinuxCon schedule. Keynote spearkers include Google Chris DiBona and the Raspberry Pi Foundation’s Eben Upton.

The increasing status of embedded is also reflected in corporate sponsorship of Linux kernel development, as indicated in the table below. The new Linux Kernel Development report makes note of the fact that companies primarily interested in embedded Linux have increased their investments in kernel development. Linaro, Samsung, and Texas Instruments (TI) boosted their aggregate contributions from 4.4 percent to 11 percent since the April 2012 report, says the LF.

Over the course of Linux kernel 3.x development, the number of developers involved in kernel development has grown from 1,131 to 1,392, while the number of companies providing support for the work has grown ever faster, from 191 to 243 (see table below). Since then, the top 10 corporate contributors to the kernel have comprised over 55 percent of the total contributions, says the LF.

As usual, Linux server mainstay Red Hat leads the list with 10.2 percent of the changes, followed by Intel with 8.8 percent. Texas Instruments and Linaro each has 4.1 percent, and the remaining range from 3.5 percent down to 2.3 percent, including SUSE, IBM, Samsung, Google, Vision Engraving Systems Consultants, various consultants, and Wolfson Microelectronics.
 

Google and Linux community make peace, not wakelocks

Contributions from Google are up significantly this year, notes the report. Google is involved with Linux from embedded (Android) to the desktop (Chrome OS) to the car (Self-Driving Car) to the cloud (Google Cloud). The fact that Linux server and cloud software underlies Google’s massive operations makes the company an even more avid participant.

Only a few years ago it looked as if Google was turning its back on the Linux kernel underlying Android, which appeared might be more of a fork than a flavor. Yet, Google has since made peace with the Linux kernel community over the once contentious wakelocks suspend blockers power management issue, and has increased its upstream contributions from the Android Open Source Project (AOSP).

“The longstanding squabble over Android-specific kernel features has faded completely into the background,” states the report. “The much-discussed ‘wakelocks’ feature has been quietly replaced by a different mainline solution which is used in the latest Android devices.”
 

ARM chips in

In recent years, Linaro, an open source tools company created by ARM and many of its major semiconductor partners, has been actively improving the notoriously sloppy ARM support in the Linux kernel. ARM chipmakers are also contributing to the kernel on their own. The leader here is TI, but Samsung, Broadcom, Nvidia, Freescale, Qualcomm, and ARM itself also make the LF’s top 30 contributor list.

Samsung and Intel are also major supporters of the Linux Foundation’s Tizen project, along with Intel. In addition, Intel is a major contributor to the LF’s Yocto Project, which is increasingly unifying embedded Linux distributions under its common development framework.

Microsoft appeared on the list for the first time in 2012, primarily by contributing drivers to lure developers to its Hyper-V virtualization platform. It was entirely missing this year, however. Another vendor missing from the list was Novell, which had previously been number three behind Intel, but was swallowed up by Attachmate, which spun off the open source Linux side of the operation as SUSE. The latter is now in fifth place behind Linaro.
 

Faster, faster…

More developers and companies are contributing to Linux than ever before with Linux kernel 3.10. The other side of this chicken-and-egg equation is that more changes (patches) are being contributed at a faster rate than ever before. The number of changes have increased over the years, from 9,153 in version 3.0, which was released in July, 2011, to 13,367 in Linux 3.10, released in July of this year.

As release cycles have tightened up to approximately 8 to 12 weeks, the number of changes per hour has increased even more dramatically, from 5.96 in version 3.0 to 9.02 in 3.10, says the report. To the concern of some — including in the past, Linux creator and kernel release gatekeeper Linus Torvalds — the number of lines of code has increased steadily since release 3.0, from 36,788 files and 14,651,135 lines of code to 43,029 files and 16,961,031 lines in 3.10.

Since the beginning of the “git era” with kernel 2.6.11, the top ten individual developers have contributed 30,420 changes — 8.4 percent of the total. The top thirty developers contributed just over 18 percent of the total. The leader has been Al Viro (1.2 percent of the changes), followed by David S. Miller and Takashi Iwal, both with 1.0 percent. Since version 3.2, Viro was in third place with 1.4 percent, following Mark Brown and H. Hartley Sweeten, which led with 2.3 percent of the changes. Among code reviewers signing off on changes done by others, Greg Kroah-Hartman leads the list by far with 12.5 percent.

The changes that have been merged into the mainline over the last year and a half represent a “vast array of important new features,” says the report. These are said to include full tickless operation, user namespaces, KVM and Xen virtualization for ARM, per-entity load tracking in the scheduler, user-space checkpoint/ restart, 64-bit ARM architecture support, the F2FS flash-oriented filesystem, and “many networking improvements aimed at the latency and bufferbloat problems.” Developers have also added two independent subsystems providing fast caching for block storage devices.

The Linux Kernel Development report is co-authored by Jon Corbet, Linux kernel developer and editor of LWN.net; Greg Kroah-Hartman, Linux kernel maintainer and Linux Foundation fellow; and Amanda McPherson, the LF’s vice president of marketing and developer services.

A live video stream of LinuxCom keynote sessions may be found here. Of particular note is the Linux kernel panel, to be held Wed., Sep. 18 at 9:30 a.m. CT. It’s hosted by Corbet, and includes Torvalds, Kroah-Hartman, Red Hat’s Tejun Heo, and Intel’s Sarah Sharp. Earlier this summer, Sharp criticized Torvalds for his coarse language and lack of civility in emails and forum postings related to kernel development. Will sparks fly, or will Linus turn into Mr. Rodgers and promise to clean up his act? Stay tuned.

The Linux Foundation’s Linux Kernel Development Report is available for free download following registration from the LF’s website, here.