Linux Ker­nel Development

von Jona­than Cor­bet, Greg Koah-​Hartmann, Amanda McPh­er­son | 01.12.2010

The ker­nel which forms the core of the Linux sys­tem is the result of one of the lar­gest coope­ra­tive soft­ware pro­jects ever attemp­ted. Regu­lar 2 – 3 month relea­ses deli­ver sta­ble updates to Linux users, each with signi­fi­cant new fea­tures, added device sup­port, and impro­ved per­for­mance. The rate of change in the ker­nel is high and incre­a­sing, with appro­xi­mately 10,000 patches going into each recent ker­nel release. These relea­ses each con­tain the work of over 1000 deve­l­o­pers rep­re­sen­ting around 200 cor­po­ra­ti­ons. Since 2005, over 6100 indi­vi­dual deve­l­o­pers from over 600 dif­fe­rent com­pa­nies have con­tri­bu­ted to the ker­nel. The Linux ker­nel, thus, has become a com­mon resource deve­l­o­ped on a mas­sive scale by com­pa­nies which are fierce com­pe­ti­tors in other areas. The first ver­sion of this study was publis­hed in 2008; it was then updated in 2009. That update noted a num­ber of chan­ges, inclu­ding a 10% increase in the num­ber of deve­l­o­pers par­ti­ci­pa­ting in each release cycle, a nota­ble increase in the num­ber of com­pa­nies par­ti­ci­pa­ting, and a tri­pling of the rate at which code is being added to the ker­nel. At that time, all of the num­bers were in a period of rapid increase.

As docu­men­ted in the last paper, in 2009 the Linux com­mu­nity saw, with the release of 2.6.30, a peak in the lines of code added. This can lar­gely be attri­bu­ted to signi­fi­cant new fea­tures being added to the ker­nel, most nota­bly the first addi­ti­ons of Btrfs, perf and ftrace, as well as the peak of the inflow from the Linux-​staging tree that had been hap­pe­ning for some time.

This update shows a slightly dif­fe­rent pic­ture. The num­ber of com­mits peaked with the 2.6.30 release; the num­ber of com­mits for 2.6.35 was 18% lower. Most other metrics have fal­len as well.

In short, we see a step back from the fren­zied activity of 2.6.30 even though the num­ber of deve­l­o­pers invol­ved has fal­len only slightly since its peak in 2.6.32.
The num­bers in this edi­tion of the paper reflect the natu­ral deve­lop­ment cycle of an ope­ra­ting sys­tem that had major pie­ces added/​changed in the pre­vious year. Of course the Linux ker­nel com­mu­nity is still hard at work and gro­wing. In fact, there have been 1.5 mil­lion lines of code added to the ker­nel since the 2009 update. Since the last paper, addi­ti­ons and chan­ges trans­late to an ama­zing 9,058 lines added, 4,495 lines remo­ved, and 1,978 lines chan­ged every day — wee­kends and holi­days inclu­ded.

The data in this year’s update also shows a good showing of new play­ers in the Linux ker­nel deve­lop­ment space from the world of mobile/​consumer elec­tro­nics and embed­ded tech­no­logy (and their suppliers). This is a healthy deve­lop­ment and not sur­pri­sing given the growth of Linux usage in embed­ded devices, even though the aut­hors would like to see more com­pa­nies from that space par­ti­ci­pate in the Linux deve­lop­ment com­mu­nity.

The over­all pic­ture shows a robust deve­lop­ment com­mu­nity which con­ti­nues to grow both in size and in pro­duc­tivity […].

Wei­ter­füh­rende Links:
http://​ker​nel​ne​w​bies​.org/

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