Statistics from the 3.7 development cycle

The 3.7-rc7 prepatch came out on November 25; it may well be the last prepatch for the 3.7 development cycle. 3.7 was one of the more active cycles in recent history, with nearly 12,000 non-merge changesets incorporated by the time of this writing. It's time for our traditional look at what was done during this cycle and where all that work came from.

The 3.7 merge window was especially busy this time around. Here are some counts for recent kernels:

Kernel	-rc1	Total
3.0	7,333	9,153
3.1	7,202	8,693
3.2	10,214	11,881
3.3	8,899	10,550
3.4	9,249	10,899
3.5	9,534	10,957
3.6	8,587	10,247
3.7	10,409	11,815

The 3.7 development cycle, thus, saw the most active merge window in the 3.x era; it is, in fact, the most active merge window ever. Even allowing for the fact that 3.7 will add a few more changesets before final release, the 2.6.25 kernel, at 12,243 changesets total, will probably still hold the record for the most active development cycle ever, but the 2.6.25 merge window only saw 9,450 changesets merged. One could conclude from these numbers that we are getting better at getting our changes in during the merge window — and at having fewer things to fix thereafter.

Nearly 395,000 lines of code were removed from the kernel this time around. That must be balanced against the 719,000 lines that were added, though; the kernel grew by almost 324,000 lines as a result.

1,271 developers contributed to the 3.7 kernel — a relatively high number, but not out of line with previous development cycles. The lists of the most active developers do see some changes this time around, though:

Most active 3.7 developers

By changesets H Hartley Sweeten 417 3.5% Antti Palosaari 216 1.8% Al Viro 167 1.4% Wei Yongjun 145 1.2% Sachin Kamat 138 1.2% Mark Brown 136 1.2% Eric W. Biederman 130 1.1% Daniel Vetter 122 1.0% David Howells 119 1.0% Hans Verkuil 119 1.0% Greg Kroah-Hartman 116 1.0% Arnd Bergmann 112 0.9% Peter Senna Tschudin 104 0.9% Ben Skeggs 97 0.8% Peter Ujfalusi 96 0.8% Ian Abbott 96 0.8% Devendra Naga 90 0.8% David S. Miller 84 0.7% Takashi Iwai 83 0.7% Johannes Berg 78 0.7%

By changed lines David Howells 65206 7.6% Ben Skeggs 50282 5.8% David Daney 46825 5.4% Arnd Bergmann 17505 2.0% Sebastian Andrzej Siewior 16088 1.9% Daniel Cotey 14157 1.6% H Hartley Sweeten 13566 1.6% Catalin Marinas 13519 1.6% Antti Palosaari 12336 1.4% Bill Pemberton 10935 1.3% Dan Magenheimer 10509 1.2% Ezequiel Garcia 10211 1.2% David S. Miller 9258 1.1% Hans Verkuil 8686 1.0% Will Deacon 8404 1.0% Shawn Guo 7464 0.9% Alois Schlögl 7301 0.8% Roland Stigge 6987 0.8% Greg Kroah-Hartman 6920 0.8% Laurent Pinchart 6107 0.7%

In a repeat of his 3.6 performance, H. Hartley Sweeten hit the top of the by-changesets list with a vast number of patches preparing the comedi drivers for graduation from the staging tree (removing over 5000 lines of code in the process). Antti Palosaari did a lot of work on drivers in the Video4Linux2 subsystem. Al Viro continues to refactor and clean up the VFS and core kernel areas with some excursions into most architecture subtrees. Wei Yongjun and Sachin Kamat both did a lot of cleanup work all over the driver tree.

David Howells ended up at the top of the "lines changed" column mostly by virtue of the user-space API header file thrashup, but he also contributed code for module signing and more. Ben Skeggs merged a major reworking of the nouveau driver, David Daney improved support for MIPS OCTEON processors, Arnd Bergmann's many patches were dominated by the removal of the unused mach-bcmring architecture code, and Sebastian Andrzej Siewior did a lot of work on the USB gadget driver subsystem.

Worth noting in passing: Fengguang Wu is credited with 63 bug reports during this cycle, almost 11% of the total. The others with at least ten reports are Dan Carpenter (21), Randy Dunlap (16), Stephen Rothwell (15), Paul McKenney (11), and Alex Lyakas (10). Every one of those reports resulted in a bug that was fixed before this kernel was released in stable form.

An even 200 employers (that we know about) contributed during the 3.7 cycle. The most active of these were:

Most active 3.7 employers

By changesets (None) 1435 12.1% Red Hat 1159 9.8% (Unknown) 843 7.1% Intel 800 6.8% Texas Instruments 597 5.1% IBM 516 4.4% Linaro 509 4.3% Vision Engraving Systems 417 3.5% SUSE 356 3.0% Google 245 2.1% Samsung 198 1.7% Freescale 181 1.5% Oracle 177 1.5% Wolfson Microelectronics 148 1.3% AMD 144 1.2% Trend Micro 144 1.2% Cisco 138 1.2% Linux Foundation 132 1.1% Arista Networks 130 1.1% NVIDIA 123 1.0%

By lines changed Red Hat 157023 18.2% (None) 80191 9.3% (Unknown) 71992 8.3% Cavium 46757 5.4% IBM 39227 4.5% Intel 33381 3.9% Linaro 28900 3.4% Texas Instruments 28493 3.3% ARM 24913 2.9% Oracle 24095 2.8% NVIDIA 19167 2.2% linutronix 17211 2.0% Vision Engraving Systems 14844 1.7% Samsung 14519 1.7% Microtrol S.R.L. 12800 1.5% PHILOSYS Software 10311 1.2% SUSE 10226 1.2% Marvell 10067 1.2% Cisco 9828 1.1% Pengutronix 9793 1.1%

There are few surprises here. Texas Instruments has reached a new high in its contribution volume, a trend which, unfortunately, may not continue after the recent changes play out there. AMD, too, seems unlikely to remain on this list in the future. Meanwhile Red Hat maintains its place at the top of the list, where it has been since we first started generating these statistics.

And that is where things stand as the 3.7 kernel approaches its final release. Things appear to be running smoothly, with most development cycles taking less than 70 days to complete (if there is no 3.7-rc8, this cycle will run about 64 days). Stay tuned for the about-to-begin 3.8 cycle, with a release to be expected in early February, 2013.

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