Contribution statistics for the 3.10 development cycle

The 3.10 kernel development cycle is nearing its completion; as of this writing, the 3.10-rc7 prepatch is out and the kernel appears to be stabilizing as expected. As predicted, 3.10 has turned out to be the busiest development cycle ever, with almost 13,500 non-merge changesets pulled into the mainline repository (so far). What follows is LWN's traditional look at where those changes came from.

3.9 set a record of its own, with 1,388 developers contributing changes. So far, with a mere 1,374 contributors, 3.10 falls short of that record, but that situation clearly could change before the final release is made. The size of our development community, it seems, continues to increase.

The most active 3.10 developers were:

Most active 3.10 developers

By changesets H Hartley Sweeten 392 2.9% Jingoo Han 299 2.2% Hans Verkuil 293 2.2% Alex Elder 268 2.0% Al Viro 205 1.5% Felipe Balbi 202 1.5% Sachin Kamat 192 1.4% Laurent Pinchart 174 1.3% Johan Hovold 159 1.2% Mauro Carvalho Chehab 158 1.2% Wei Yongjun 139 1.0% Arnd Bergmann 138 1.0% Eduardo Valentin 138 1.0% Axel Lin 112 0.8% Lee Jones 111 0.8% Lars-Peter Clausen 99 0.7% Kuninori Morimoto 98 0.7% Tejun Heo 97 0.7% Mark Brown 97 0.7% Johannes Berg 96 0.7%

By changed lines Joe Perches 34561 4.5% Hans Verkuil 18739 2.4% Kent Overstreet 18690 2.4% Larry Finger 17222 2.2% Greg Kroah-Hartman 16610 2.2% Shawn Guo 12879 1.7% Dave Chinner 12838 1.7% Paul Zimmerman 12637 1.6% H Hartley Sweeten 12518 1.6% Al Viro 11116 1.4% Andrey Smirnov 11107 1.4% Mauro Carvalho Chehab 9726 1.3% Laurent Pinchart 9258 1.2% Jussi Kivilinna 8960 1.2% Lee Jones 8598 1.1% Sylwester Nawrocki 8305 1.1% Artem Bityutskiy 8094 1.0% Dave Airlie 7546 1.0% Guenter Roeck 7510 1.0% Sanjay Lal 7428 1.0%

H. Hartley Sweeten's position at the top of the list seems like a permanent aspect of these reports as he continues his work on the endless task of cleaning up the Comedi drivers in the staging tree. Jingoo Han contributed a long list of driver cleanup patches, moving the code toward the use of standard helper functions and the "managed" resource allocation API. Hans Verkuil improved a number of video acquisition drivers as part of his new(ish) role as the maintainer of the Video4Linux subsystem. Alex Elder's work is focused on the Ceph filesystem and associated "RADOS" block device, and Al Viro implemented a large number of core kernel improvements and API changes. Together, these five developers accounted for nearly 11% of all the changes going into the kernel.

In the "lines changed" column, Joe Perches topped the list with a set of patches effecting whitespace cleanups, printk() format changes, checkpatch.pl tweaks, and more. Kent Overstreet added the bcache block caching subsystem and a number of asynchronous I/O improvements. Larry Finger's 17 patches added new features and device support to the rtlwifi driver, and Greg Kroah-Hartman removed the Android "CCG" USB gadget driver from the staging tree.

Just over 200 employers are known to have supported work on the 3.10 kernel. The most active of these were:

Most active 3.10 employers

By changesets (None) 1495 11.1% Red Hat 1269 9.4% Intel 912 6.8% Linaro 877 6.5% Texas Instruments 765 5.7% (Unknown) 746 5.5% Samsung 615 4.6% IBM 402 3.0% Vision Engraving Systems 392 2.9% Google 350 2.6% SUSE 332 2.5% Renesas Electronics 331 2.5% Cisco 300 2.2% Inktank Storage 277 2.1% Broadcom 182 1.3% NVidia 180 1.3% Freescale 175 1.3% Oracle 175 1.3% Trend Micro 139 1.0% Fujitsu 138 1.0%

By lines changed (None) 118326 15.3% Red Hat 88080 11.4% Linaro 64697 8.4% Intel 50641 6.6% Google 33342 4.3% Cisco 24109 3.1% (Unknown) 24033 3.1% Samsung 20893 2.7% Texas Instruments 20289 2.6% NVidia 18470 2.4% Linux Foundation 16759 2.2% Renesas Electronics 15777 2.0% IBM 14385 1.9% QLogic 14165 1.8% Synopsys 13698 1.8% Vision Engraving Systems 13111 1.7% Broadcom 12770 1.7% Synapse Product Development 11107 1.4% OpenSource AB 9584 1.2% SUSE 9479 1.2%

With 3.10, Red Hat regained its usual place as the company with the most contributions, though even Red Hat, once again, falls short of the contributions from volunteers. The increase in contributions from the mobile and embedded community continues its impressive growth; Linaro, in particular, continues to grow, with 42 developers contributing code under its name to 3.10.

In summary, the kernel's busiest development cycle ever shows the continuation of a number of patterns that have been observed for a while: increasing participation from the mobile and embedded worlds, more developers, and more companies. There was a slight uptick in volunteer contributors this time around, but it is not at all clear that the long-term decline in that area has been interrupted. As a whole, the kernel development machine continues to operate in its familiar, predictable, and productive manner.

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