Who wrote 2.6.33

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The release of the 2.6.33-rc7 prepatch indicates that this development cycle is headed toward a close, even if Linus thinks that a -rc8 will be necessary. As has become traditional, LWN has taken a look at some statistics related to this cycle and where the code came from.

As of this writing, 10,500 non-merge commits have found their way into 2.6.33 - fairly normal by recent standards. These changes added almost 900,000 lines while deleting almost 520,000 others; as a result, the kernel grew by a mere 380,000 lines this time around. According to the most recent regression list, 97 regressions have been reported in 2.6.33, of which 20 remain unresolved.

Some 1,152 developers contributed code to 2.6.33. The most active of those were:

Most active 2.6.33 developers By changesets Ben Hutchings 145 1.4% Frederic Weisbecker 145 1.4% Arnaldo Carvalho de Melo 138 1.3% Luis R. Rodriguez 130 1.2% Masami Hiramatsu 128 1.2% Bartlomiej Zolnierkiewicz 124 1.2% Eric Dumazet 108 1.0% Alan Cox 105 1.0% Manu Abraham 102 1.0% Thomas Gleixner 101 1.0% Eric W. Biederman 97 0.9% Roel Kluin 91 0.9% Alexander Duyck 88 0.8% Paul Mundt 87 0.8% Johannes Berg 80 0.8% Wey-Yi Guy 77 0.7% Alex Deucher 76 0.7% Jean Delvare 73 0.7% Al Viro 72 0.7% By changed lines Bartlomiej Zolnierkiewicz 206468 18.1% Henk de Groot 50355 4.4% Jerry Chuang 49627 4.3% Ben Skeggs 37555 3.3% Philipp Reisner 23182 2.0% Eilon Greenstein 23123 2.0% Tomi Valkeinen 22508 2.0% Mike Frysinger 13116 1.1% Ben Hutchings 12680 1.1% Jakob Bornecrantz 11613 1.0% Wu Zhangjin 11325 1.0% Greg Kroah-Hartman 10468 0.9% Rajendra Nayak 9978 0.9% Manu Abraham 9625 0.8% jack wang 9171 0.8% Masami Hiramatsu 8973 0.8% Alan Cox 7672 0.7% David VomLehn 7331 0.6% Arnaldo Carvalho de Melo 7217 0.6%

While some of the usual names appear at the top of this list, there are some newcomers as well. Ben Hutchings did a lot of work with network drivers, including the addition of the SolarFlare SFC9000 driver (which has several co-authors). Frederic Weisbecker has been active in a number of areas, adding the hardware breakpoints code, removing the big kernel lock from the reiserfs filesystem, and working with tracing and the perf tool. Arnaldo Carvalho de Melo's work is almost all with the perf events subsystem and the perf tool in particular. Luis Rodriguez continues to work all over the wireless driver subsystem, and with the Atheros drivers in particular, and Masami Hiramatsu's largest contribution is the dynamic probing work.

In the "lines changed" column, Bartlomiej Zolnierkiewicz continues to work in fixing up some wireless drivers in the staging tree, deleting a lot of code in the process; he also continues his IDE driver work. Henk de Groot added the Agere driver for HERMES II chipsets, Jerry Chuang added the Realtek rtl8192u driver, and Ben Skeggs added much of the Nouveau driver.

Contributions to 2.6.33 came from 182 employers that your editor was able to identify. The most active of those are:

Most active 2.6.33 employers By changesets (None) 1535 14.6% Red Hat 1223 11.6% Intel 1011 9.6% (Unknown) 868 8.3% IBM 500 4.8% Novell 390 3.7% Nokia 319 3.0% (Consultant) 316 3.0% Fujitsu 204 1.9% Texas Instruments 199 1.9% Atheros Communications 169 1.6% (Academia) 166 1.6% AMD 165 1.6% Oracle 136 1.3% Analog Devices 130 1.2% Renesas Technology 126 1.2% Pengutronix 125 1.2% HP 124 1.2% Solarflare Communications 123 1.2% By lines changed (None) 304895 26.7% (Unknown) 109716 9.6% Red Hat 92991 8.1% Broadcom 54272 4.8% Realtek 49951 4.4% Intel 46302 4.1% Nokia 37505 3.3% Novell 27235 2.4% IBM 26783 2.3% (Consultant) 25845 2.3% Texas Instruments 24232 2.1% LINBIT 23247 2.0% Analog Devices 19677 1.7% VMWare 16045 1.4% Samsung 15707 1.4% Solarflare Communications 15054 1.3% JiangSu Lemote Corp. 11439 1.0% AMD 9218 0.8% Universal Scientific Industrial Co. 9194 0.8%

As usual, Red Hat maintains its position at the top of the list, but others are gaining; we may yet see a day when Red Hat is just one of several major contributors. Some readers may be surprised to see Broadcom near the top of the list, given that this company's reputation for contribution is not the best. The truth of the matter is that Broadcom has several developers contributing to various drivers in the networking and SCSI subsystems; it's only in the wireless realm that the trouble starts.

For the fun of it, your editor typed the "changeset percent" numbers for the last ten releases into a spreadsheet and got this plot:

The percentages are surprisingly stable over the course of almost three years. The most obviously identifiable trends, perhaps, are the steady increases in the contributions from Intel and Nokia.

All told, the process continues to function smoothly. The occasional complaint about certain companies not fully participating in the process notwithstanding, the picture is one of hundreds of companies cooperating to a high degree to create the Linux kernel despite their fierce competition elsewhere. The significant percentage of code coming from developers working on their own time shows that Linux is not just a corporate phenomenon, though. We have built a development community which is able to incorporate the interests and work of an astonishingly wide variety of people into a single kernel.

As always, thanks are due to Greg Kroah-Hartman, who has done a great deal of work to reduce the size of the "(Unknown)" entries in the tables above.

