Some 4.4 development statistics
So, naturally, it is about time to look at this cycle's development activity. As of this writing, there have been 12,854 non-merge changesets pulled into the mainline this time around. It has thus been a busy cycle, though it would be surprising if we reached the number of changes seen in 4.2 (13,694), or the all-time record (13,722) set for 3.15.
The number of developers involved thus far is 1,548 — a large number, but slightly short of the 1,600 seen in 4.3. We may yet reach the 1,569 seen in the 4.2 cycle, though. Of those 1,548 contributors, 246 made their first kernel contribution in this development cycle — the lowest number since 3.13. The most active developers this time around were:
Most active 4.4 developers
By changesets H Hartley Sweeten 288 2.2% Mateusz Kulikowski 218 1.7% Chaehyun Lim 179 1.4% Leo Kim 167 1.3% Eric W. Biederman 163 1.3% Shraddha Barke 147 1.1% Ville Syrjälä 144 1.1% Arnd Bergmann 143 1.1% Eric Dumazet 123 1.0% Tony Cho 108 0.8% Geert Uytterhoeven 105 0.8% Glen Lee 105 0.8% Russell King 104 0.8% Javier Martinez Canillas 101 0.8% Sudip Mukherjee 96 0.7% Christoph Hellwig 91 0.7% Mike Rapoport 91 0.7% Oleg Drokin 89 0.7% Luis de Bethencourt 89 0.7% Andy Shevchenko 82 0.6%
By changed lines Alex Deucher 32203 5.0% Sreekanth Reddy 24009 3.7% Yuval Mintz 20622 3.2% Christoph Hellwig 15656 2.4% huangdaode 14725 2.3% Michael Chan 13137 2.0% Lv Zheng 9887 1.5% Oleg Drokin 8434 1.3% Deepa Dinamani 7797 1.2% Jes Sorensen 7737 1.2% Peter Senna Tschudin 7676 1.2% Sudeep Dutt 6881 1.1% Leo Kim 6664 1.0% Alexander Shishkin 6612 1.0% Arnd Bergmann 5893 0.9% Takashi Sakamoto 5837 0.9% Jiri Pirko 5350 0.8% Adam Thomson 5123 0.8% Eric Anholt 5041 0.8% H Hartley Sweeten 5030 0.8%
After an absence for a few development cycles, H. Hartley Sweeten is back at the top of the per-changeset list for the ongoing work on the Comedi drivers in the staging tree. This code, at just under 100,000 lines, has now seen nearly 8,000 patches — and the work continues. Mateusz Kulikowski worked entirely with the rtl8192e staging driver, while Chaehyun Lim and Leo Kim both fixed up the wilc1000 staging driver. Eric Biederman is engaged in a substantial reworking of how the network stack handles network namespaces, with an emphasis on proper handling of packets that cross namespaces.
On the lines-changed side, Alex Deucher continues to work on the AMD graphics drivers, Sreekanth Reddy removed a bunch of code from the mpt2sas driver (and, as a result, was the developer removing the most code in this cycle), and Yuval Mintz added a couple of Qlogic Ethernet drivers. Christoph Hellwig did a fair amount of cleanup throughout the driver and block subsystems, while huangdaode (the only name that appears in the logs) added support for the Hisilicon network subsystem.
The sum of these developers' effort resulted in the net addition of 242,000 lines of code to the kernel in this development cycle.
Work on 4.4 was supported by 202 employers that we could identify, a slight increase from 4.3. The most active companies working on 4.4 were:
Most active 4.4 employers
By changesets Intel 1660 12.9% (Unknown) 1139 8.9% (None) 684 5.3% Samsung 670 5.2% Red Hat 655 5.1% Atmel 449 3.5% Linaro 448 3.5% (Consultant) 419 3.3% Outreachy 400 3.1% IBM 302 2.3% Vision Engraving Systems 288 2.2% 273 2.1% SUSE 257 2.0% ARM 226 1.8% Texas Instruments 210 1.6% Freescale 208 1.6% Renesas Electronics 190 1.5% AMD 177 1.4% Oracle 173 1.3% Broadcom 169 1.3%
By lines changed Intel 85390 13.3% (None) 37078 5.8% AMD 36306 5.6% Red Hat 34937 5.4% (Unknown) 33739 5.2% (Consultant) 30271 4.7% Avago Technologies 27001 4.2% QLogic 24381 3.8% Broadcom 19318 3.0% Atmel 17856 2.8% Samsung 16508 2.6% Linaro 16154 2.5% HiSilicon Technologies 15260 2.4% Outreachy 12765 2.0% Renesas Electronics 11745 1.8% Mellanox 11590 1.8% Freescale 11392 1.8% ARM 10986 1.7% IBM 10402 1.6% Texas Instruments 10345 1.6%
For many years, Red Hat stood alone at the top of both columns of this list. That situation has been changing for some time; at this point, it is more than fair to say that Red Hat has ceased to be the most active company in the kernel development community. That is not to slight the company's work, of course; Red Hat still funds many of our most active developers, and those developers, in the subsystem-maintainer role, signed off on 16% of the changes merged this time around. But, at this point, Red Hat is one of a number of top-tier companies working to improve the Linux kernel.
Speaking of signoffs, the most active developers and companies when it comes to signing off patches they did not write are:
Most non-author signoffs in 4.4
Developers Greg Kroah-Hartman 2746 21.3% David S. Miller 1048 8.1% Daniel Vetter 447 3.5% Andrew Morton 346 2.7% Mark Brown 343 2.7% Ingo Molnar 241 1.9% Arnaldo Carvalho de Melo 224 1.7% Tony Cho 210 1.6% Jeff Kirsher 209 1.6% Kalle Valo 174 1.3%
Companies Linux Foundation 2763 21.6% Red Hat 2060 16.1% Intel 1649 12.9% Linaro 820 6.4% 602 4.7% (None) 459 3.6% SUSE 392 3.1% Atmel 260 2.0% Samsung 260 2.0% 233 1.8%
The kernel's subsystem maintainers remain concentrated in relatively few companies though, arguably, they are spread out a bit more widely than they once were. While many companies are willing to support kernel development in specific areas, fewer of them see the need to support developers working in the subsystem-maintainer role.
In summary, 4.4, the final kernel development for 2015, looks pretty
typical. It was busier than most, but that, too, is typical, given the
long-term trend toward larger development cycles. That busyness does not
appear set to make this cycle longer than the 63 days that we have come to
expect, though. Despite its occasional hiccups, the kernel-development
machine continues to run smoothly.
| Index entries for this article | |
|---|---|
| Kernel | Releases/4.4 |