Some 5.9 kernel development statistics

The 5.9 kernel was released on October 11, at the end of a ten-week development cycle — the first release to take more than nine weeks since 5.4 at the end of 2019. While this cycle was not as busy as 5.8, which broke some records, it was still one of the busier ones we have seen in some time, featuring 14,858 non-merge changesets contributed by 1,914 developers. Read on for our traditional look at what those developers were up to while creating the 5.9 release.

Of the 1,914 developers contributing to 5.9, 306 made their first contribution for this release. This is the largest number of new contributors we have seen since 4.12 (which had 334 first-time contributors) was released in 2017 and, indeed, the second-highest number ever seen. All together, the 5.9 contributors added just over 730,000 lines of code and removed nearly 262,000 for a net growth of 468,000 lines of code. The busiest developers this time around were:

Most active 5.9 developers

By changesets Lee Jones 520 3.5% Christoph Hellwig 292 2.0% Randy Dunlap 261 1.8% Alexander A. Klimov 187 1.3% Ben Skeggs 137 0.9% Chris Wilson 135 0.9% Laurent Pinchart 135 0.9% Evan Quan 113 0.8% Pierre-Louis Bossart 113 0.8% Gustavo A. R. Silva 110 0.7% Likun Gao 109 0.7% Thomas Zimmermann 105 0.7% Thierry Reding 102 0.7% Colin Ian King 97 0.7% Pavel Begunkov 96 0.6% Kuninori Morimoto 95 0.6% Andy Shevchenko 91 0.6% Krzysztof Kozlowski 88 0.6% Kees Cook 83 0.6% Edward Cree 80 0.5%

By changed lines Jerry (Fangzhi) Zuo 92950 11.2% Likun Gao 77897 9.4% Bhawanpreet Lakha 28787 3.5% Mike Rapoport 18531 2.2% Edward Cree 13146 1.6% Ben Skeggs 10761 1.3% Christoph Hellwig 9286 1.1% Leo Liu 9056 1.1% Tzu-En Huang 8521 1.0% Hans Verkuil 8487 1.0% Evan Quan 8428 1.0% Laurent Pinchart 6438 0.8% Alexander Lobakin 6129 0.7% Rob Clark 5992 0.7% Chris Wilson 5934 0.7% Hyun Kwon 5839 0.7% Dmitry Osipenko 5728 0.7% Jesse Brandeburg 5335 0.6% Leon Romanovsky 5134 0.6% Jakub Kicinski 4774 0.6%

The largest number of changesets going into 5.9 came from Lee Jones, who contributed many cleanups across the device-driver subsystem. Christoph Hellwig made substantive changes across a number of kernel subsystems; this work includes the removal of set_fs() among many other things. Randy Dunlap removed duplicated words words from files all over the kernel tree, Alexander Klimov converted vast numbers of "HTTP" links to "HTTPS", and Ben Skeggs contributed a lot of improvements to the Nouveau graphics driver.

The "lines contributed" column starts with Jerry (Fangzhi) Zuo, Likun Guo, and Bhawanpreet Lakha, all of whom added more code to the massive amdgpu graphics driver. Zuo only contributed two patches, but one of them was large (and consisted only of definitions of preprocessor symbols). Mike Rapoport removed the unloved unicore32 architecture and Edward Cree did a lot of work on the Solarflare SFC network driver.

Overall, 207 employers supported work on the 5.9 kernel, a number that is consistent with previous releases. The most active employers were:

Most active 5.9 employers

By changesets (None) 1377 9.3% Intel 1336 9.0% Red Hat 1006 6.8% (Unknown) 895 6.0% AMD 848 5.7% Linaro 842 5.7% Google 662 4.5% SUSE 554 3.7% (Consultant) 504 3.4% IBM 478 3.2% Huawei Technologies 471 3.2% Facebook 385 2.6% Renesas Electronics 323 2.2% NXP Semiconductors 313 2.1% Mellanox 303 2.0% Oracle 245 1.6% NVIDIA 221 1.5% Arm 207 1.4% Code Aurora Forum 203 1.4% Texas Instruments 189 1.3%

By lines changed AMD 243874 29.4% Intel 56635 6.8% Red Hat 39347 4.8% IBM 35658 4.3% (None) 30232 3.7% Google 29715 3.6% (Unknown) 29421 3.6% Mellanox 24149 2.9% Facebook 22410 2.7% Linaro 19271 2.3% (Consultant) 18151 2.2% NVIDIA 17985 2.2% Renesas Electronics 14974 1.8% SUSE 14409 1.7% Texas Instruments 13508 1.6% Solarflare Communications 13146 1.6% Marvell 11284 1.4% NXP Semiconductors 10900 1.3% Code Aurora Forum 10817 1.3% Realtek 10260 1.2%

This is the first time in years that the largest number of changesets came from people who were working on their own time; it seems unlikely to be a change to the long-term trend toward smaller volunteer participation, but one never knows. Otherwise the employer numbers look about the same as they do in most months.

The busiest testers and bug reporters for 5.9 were:

Test and report credits in 5.9
Tested-by Andrew Bowers 71 7.5% Aaron Brown 38 4.0% Nicolas Saenz Julienne 28 2.9% Arnaldo Carvalho de Melo 28 2.9% Sedat Dilek 24 2.5% Stan Johnson 21 2.2% 周正 (Zhou Zheng) 18 1.9% John Donnelly 17 1.8% Dmitry Baryshkov 16 1.7% Alexei Starovoitov 16 1.7%	Reported-by kernel test robot 169 17.1% Syzbot 91 9.2% Hulk Robot 67 6.8% Dan Carpenter 23 2.3% Stephen Rothwell 17 1.7% Naresh Kamboju 16 1.6% Randy Dunlap 16 1.6% Lars-Peter Clausen 13 1.3% Qian Cai 12 1.2% Colin Ian King 8 0.8%

Automated testing systems continue to be the most prolific source of bug reports; they were responsible for just over one-third of the total in the 5.9 cycle.

The developers with the most review credits this time around were:

Review credits in 5.9
Rob Herring	195	3.0%
Alex Deucher	162	2.5%
David Sterba	131	2.0%
Lyude Paul	130	2.0%
Hawking Zhang	121	1.9%
Christoph Hellwig	107	1.7%
Florian Fainelli	103	1.6%
Andy Shevchenko	95	1.5%
Jiri Pirko	82	1.3%
Darrick J. Wong	80	1.2%

A total of 5,235 commits for 5.9 contained Reviewed-by tags; that is 35% of the total, which is up slightly from 5.8.

All told, 5.9 looks like another fairly routine development cycle that is a little busier than the average. Once again, it seems that the ongoing global pandemic has not hurt the pace of Linux kernel development; it might even possibly have encouraged the larger-than-normal number of changes from first-time and volunteer developers. The kernel community is clearly running at full speed as it heads into the 5.10 development cycle.

Index entries for this article
Kernel	Releases/5.9

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