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Linux: More contributors, more code

A lot more than just Linus Torvalds

Averaged over the past four and a half years, the top ten individuals have contributed 12 per cent of the Linux kernel code, and the top 30 developers accounted for 25 per cent of the code. And guess who has fallen off the top 30 Linux kernel development list? None other than Linus Torvalds, who has a total of 729 changes from Linux 2.6.11 through 2.6.30, with 254 of them spanning from Linux 2.6.24 through 2.6.30.

"Linus remains an active and crucial part of the development process," the report quickly says, and "his contribution cannot be measured just by the number of changes made. (Obscure technical detail: these numbers do not count “merge commits,” where one set of changes is merged into another. Linus Torvalds generates large numbers of merge commits; had these been counted he would have shown up on this list.) Linus of course does a great deal of reviewing and signoffs of code."

If you look at the Git repository for Linux 2.6.12 through Linux 2.6.30, Bartlomiej Zolnierkiewicz, who is a student at Warsaw University of Technology, tops the list, with 1,169 changes (1.8 per cent of the total), just edging out Ingo Molnar of Red Hat, who has racked up 1,164 changes to the kernel in the past few years. Number three on the list is David Miller, who is one of the maintainers of the TCP/IP networking stack and the key developer who ports Linux to the Sparc architecture. Chris Mason, who works at Oracle, is number four, with 851 changes, followed by Takashi Iwai, of Novell, with 711 changes.

As you might expect from an open source effort such as Linux kernel development, those claiming no affiliation or corporate sponsorship account for most of the changes in the Linux 2.6 kernel since Linux 2.6.24, with a total of 13,850 changes to the kernel and representing 21.1 per cent of all changes; those with an unknown affiliation accounted for 2,765 changes, or 4.2 per cent.

Of the corporate sponsors, Red Hat accounts for the most changes in the latest releases of the Linux kernel, with 7,897 (12 per cent), followed by IBM with 4,150 changes (6.3 per cent), Novell with 4,021 changes (6.1 per cent), Intel with 3,923 changes (6 per cent), and Oracle with 2,003 changes (3.1 per cent).

While these programmers make the changes to Linux, the developers who sign off on the changes also carry a heavy burden, with Andrew Morton accounting for 6,515 approvals, or about 10.5 per cent of the total since Linux 2.6.24, followed by Ingo Molnar with 6,174 signoffs and David Miller with 5,954. Linus Torvalds shows up as number nine on this list, with 1,664 signoffs since Linux 2.6.24, or about 2.7 per cent of the burden.

By employer, Red Hat does the most signing off by far, with 22,652 or 36.4 per cent of the total, followed by Google with 6,530 (10.5 per cent), and Novell with 5,076 (8.2 per cent). The Linux Foundation gets credit for Torvalds' signoffs, since it writes his paycheck. ®

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