Who wrote - and approved - 2.6.22
As of this writing, just over 6,000 changesets have been accepted for 2.6.22. Those patches were contributed by 885 different developers, added 494,000 lines, and deleted 241,000 other lines (without counting renames, which would otherwise increase both numbers by about 60,000 lines). That makes 2.6.22 a large change relative to its immediate predecessors:
Release Developers Changesets Lines
addedLines
removed2.6.20 741 4983 286,000 160,000 2.6.21 842 5349 343,000 199,000 2.6.22-rc4+ 885 6093 494,000 241,000
Here's the top contributors of those changes:
Most active 2.6.22 developers
By changesets David S. Miller 175 3.0% Kristian Høgsberg 109 1.9% Stephen Hemminger 86 1.5% Arnaldo Carvalho de Melo 82 1.4% Andrew Morton 79 1.3% Stefan Richter 79 1.3% Christoph Lameter 77 1.3% Patrick McHardy 76 1.3% Jean Delvare 75 1.3% Dmitry Torokhov 70 1.2% Stephen Rothwell 68 1.2% Paul Mundt 66 1.1% David Brownell 65 1.1% Jeff Dike 63 1.1% Alan Cox 60 1.0% Andi Kleen 59 1.0% Antonino Daplas 58 1.0% Adrian Bunk 58 1.0% Tejun Heo 57 1.0% Russell King 57 1.0%
By changed lines Bryan Wu 77594 12.9% David Howells 23310 3.9% Marcelo Tosatti 22351 3.7% Patrick McHardy 21746 3.6% Jiri Benc 18328 3.0% Hans Verkuil 13683 2.3% David S. Miller 13595 2.3% Roland Dreier 12247 2.0% Artem B. Bityutskiy 12065 2.0% Kristian Høgsberg 11153 1.9% Robert P. J. Day 7554 1.3% Christoph Lameter 7378 1.2% Andrew Victor 6638 1.1% Mike Frysinger 6313 1.0% David Brownell 6033 1.0% Michael Chan 5851 1.0% Andi Kleen 5431 0.9% David Gibson 5321 0.9% Nobuhiro Iwamatsu 5296 0.9% Mark Fasheh 4921 0.8%
Bryan Wu makes it to the top of the list of contributors (by lines changed) by virtue of being the person to contribute support for the Blackfin architecture. David Howells contributed the AF_RXRPC and AFS filesystem work; Marcelo Tosatti wrote the OLPC "Libertas" wireless driver, and Jiri Benc's name appears on the mac80211 stack.
When broken down by employer, the (approximate, as always) numbers come out like this:
Most active 2.6.22 employers
By changesets (Unknown) 1766 30.2% Red Hat 720 12.3% IBM 601 10.3% Novell 411 7.0% (None) 245 4.2% Intel 203 3.5% Oracle 127 2.2% (Consultant) 119 2.0% Linux Foundation 116 2.0% 111 1.9% SGI 93 1.6% Nokia 83 1.4% Freescale 80 1.4% Astaro 76 1.3% XenSource 56 1.0% MontaVista 56 1.0% Qumranet 55 0.9% HP 53 0.9% QLogic 52 0.9% Analog Devices 49 0.8%
By lines changed (Unknown) 130164 21.6% Red Hat 104627 17.4% Analog Devices 84561 14.0% Novell 41366 6.9% IBM 33629 5.6% Astaro 22065 3.7% (None) 20097 3.3% (Consultant) 15403 2.6% Linutronix 13585 2.3% Intel 12288 2.0% Cisco 12280 2.0% Oracle 10482 1.7% Freescale 10116 1.7% SGI 8639 1.4% Nokia 7328 1.2% SANPeople 7045 1.2% Broadcom 5952 1.0% MontaVista 5810 1.0% Linux Foundation 5746 1.0% Atmel 5220 0.9%
One thing which jumps out here is that the amount of code contributed by developers known to be working on their own time has dropped; 2.6.22 will be one of the most corporate kernels yet.
Looking at the developers who put Signed-off-by lines onto patches yields some interesting results. If one tabulates all 12,678 signoffs in 2.6.22, the results look like this:
Developers with the most signoffs (total 12678) Andrew Morton 1415 11.2% Linus Torvalds 1299 10.2% David S. Miller 814 6.4% Paul Mackerras 381 3.0% Jeff Garzik 344 2.7% Andi Kleen 252 2.0% Greg Kroah-Hartman 236 1.9% Mauro Carvalho Chehab 236 1.9% Stefan Richter 210 1.7% Russell King 189 1.5% James Bottomley 176 1.4% Jaroslav Kysela 145 1.1% Takashi Iwai 131 1.0% Len Brown 126 1.0% Kristian Høgsberg 126 1.0% Patrick McHardy 117 0.9% Jean Delvare 110 0.9% Roland Dreier 109 0.9% Antonino Daplas 106 0.8% Dmitry Torokhov 105 0.8%
All authors must sign off on their code. Additionally, any maintainer who passes a patch up toward the mainline adds a signoff indicating that he or she believes the code is legitimate and suitable for inclusion. If one excludes signoffs by the author of each patch, the remaining 7,000 signoffs are (almost) all by people through whom the code has passed (a few of them are by additional authors of the patch). Those adding non-author signoffs can thus be thought of as the gatekeepers through whom each patch must pass. Non-author signoffs break down like this:
Non-author signoffs (total 7028) Andrew Morton 1336 19.0% Linus Torvalds 1279 18.2% David S. Miller 640 9.1% Paul Mackerras 371 5.3% Jeff Garzik 322 4.6% Greg Kroah-Hartman 222 3.2% Mauro Carvalho Chehab 216 3.1% Andi Kleen 193 2.7% James Bottomley 163 2.3% Jaroslav Kysela 142 2.0% Russell King 132 1.9% Stefan Richter 131 1.9% Len Brown 115 1.6% John W. Linville 85 1.2% Roland Dreier 85 1.2% Takashi Iwai 79 1.1% Martin Schwidefsky 54 0.8% David Woodhouse 53 0.8% Ralf Baechle 48 0.7% Antonino Daplas 48 0.7%
In summary, 80% of the patches merged into the mainline kernel passed through the twenty developers listed above. One can take another step, and look at the number of non-author signoffs by employer:
Non-author signoffs by employer 1338 19.0% Linux Foundation 1281 18.2% Red Hat 1246 17.7% Novell 700 10.0% (Unknown) 660 9.4% IBM 553 7.9% (None) 293 4.2% Intel 193 2.7% SteelEye 163 2.3% Cisco 85 1.2% MIPS Technologies 48 0.7% Nokia 42 0.6% Astaro 41 0.6% Analog Devices 35 0.5% QLogic 35 0.5% Cendio 32 0.5% SGI 28 0.4% NetApp 28 0.4% (Consultant) 23 0.3% Oracle 22 0.3%
The bottom line: while Linux kernel development is a highly distributed
activity, the work of several hundred developers is channeled through a
surprisingly small number of individuals, and an even smaller number of
companies on its way into the mainline.
| Index entries for this article | |
|---|---|
| Kernel | Development model/Contributor statistics |
| Kernel | Releases/2.6.22 |
(Log in to post comments)
Who wrote - and approved - 2.6.22
Posted Jun 14, 2007 2:45 UTC (Thu) by pr1268 (subscriber, #24648) [Link]
A positive perspective I see is that the 'corporate' bias in the recent kernels (and a list of the very companies supporting this development) as a sign that Linux is indeed a valid, viable, and stable alternative to proprietary operating system (and related) software.
Either that, or (as I've stated before) the companies who throw resources1 at Linux are the same companies who have the most to gain from its continued development.
1Perhaps "throw resources" sounds a little harsh, but I mean it in the nicest sense of the term.
Who wrote - and approved - 2.6.22
Posted Jun 14, 2007 8:37 UTC (Thu) by xav (guest, #18536) [Link]
I think having a lot of "corporate" reviewers is a good thing. Doing codereview isn't always the most interesting thing to do, just developing is
far more fun. So having a lot of people payed by corps to do the tedious
work of reviewing code, while independant developers continue to write
their crappy drivers is IMHO a very good equilibrium point.
Xav
Who wrote - and approved - 2.6.22
Posted Jun 14, 2007 20:48 UTC (Thu) by elanthis (guest, #6227) [Link]
Silly question, but how do 20% of patches get into mainline without passing through Linux (or even Andrew) ?
Is it just that Linus doesn't sign-off when he merges patches, so the sign-offs from him are those he reviewed personally versus those reviewed by some other "trusted lieutenant" not on that top 20 list?
Who wrote - and approved - 2.6.22
Posted Jun 15, 2007 0:23 UTC (Fri) by aegl (guest, #37581) [Link]
Yes. When Linus does a "pull" from a subsystem maintainer's tree, none of the changesets get his sign-off.
Who wrote - and approved - 2.6.22
Posted Jun 15, 2007 16:25 UTC (Fri) by aegl (guest, #37581) [Link]
It isn't a sure bet that a change-set with a sign-off from Linus has actually been reviewed by him either ... when Andrew Morton sends a "patch-bomb" with several hundred e-mail messages moving code from -mm to Linus, chances are that Linus does not sit down and read each and every one of them. But they will all get a "Signed-off-by" from Linus because the GIT tool that applies patches from a mailbox adds a sign-off to each commit that is applied that way.If Andrew started using a GIT tree to transfer to Linus, then many of those "Signed-off-by: Linus" commits would just end the trail-of-blame with Andrew's sign-off.
This is sort of documented in Documentation/SubmittingPatches: "The Signed-off-by: tag indicates that the signer was involved in the development of the patch, or that he/she was in the patch's delivery path.". "In the patches delivery path" does not necessarily mean "Reviewed by".
So some care is needed when interpreting this data since some quite large parts are affected by the mechanisms used to move changes around.
Who wrote - and approved - 2.6.22
Posted Jun 16, 2007 13:05 UTC (Sat) by hingo (guest, #14792) [Link]
Surely Andrew Morton uses GIT to transfer code to Linus?If the opposite was true, then we would have just uncovered a major scoop, that Linus doesn't really do anything at all anymore, just sits around taking credit for not coding anything, not approving anything.
Who wrote - and approved - 2.6.22
Posted Jun 16, 2007 18:02 UTC (Sat) by dlang (guest, #313) [Link]
the facts are in between these two.
as I understand it, Andrew doesn't normally use git to send patches to Linus, but at the same time signed off by indicates that the person is vouching for the patch. I don't think that it's done automaticaly by the git scripts (remember, they are used by projects that don't do 'signed off by' lines)
Linus has said many times that his job is more to be a gatekeeper then a coder nowdays, but he still writes and modifies code.
David Lang
Who wrote - and approved - 2.6.22
Posted Jun 17, 2007 9:25 UTC (Sun) by hingo (guest, #14792) [Link]
Ok. What I was really wondering was that Andrew Signs off 0.8% more patches than Linus, so mathematically it's impossible to claim that some script by Linux automatically signs off everything Andrew has signed?
Who wrote - and approved - 2.6.22
Posted Jun 15, 2007 21:23 UTC (Fri) by jkm (guest, #14176) [Link]
It's fairly misleading to see Google listed at the top of non-author signoffs by employer, considering only two of the signoffs came from someone other than Andrew.
Who wrote - and approved - 2.6.22
Posted Jun 20, 2007 21:53 UTC (Wed) by roelofs (guest, #2599) [Link]
It's fairly misleading to see Google listed at the top of non-author signoffs by employer, considering only two of the signoffs came from someone other than Andrew.It's hardly any different for Linus/Linux Foundation, is it?
Keep in mind that there is at least a vague correlation between number of signoffs performed and (paid) effort expended. Red Hat just spreads theirs around a bit more. ;-)
Greg