• Jamboree15KernelDevProcessEn

CELF Technical Jamboree #15
July, 12, 2007

[original file is 08.カーネル開発の進め方.txt]
[note taken by M. Nishikawa; translated by ikoma]

How to Proceed Kernel Development

(1) Web Resources and Develpment Process

Shibata, NEC

* Self Introduction

• Promoting Linux technology in NEC
• Want engineers in Japan to have more expreiences with Linux

* What steps?

• Get information <== here

  • ==> http://jp.kernelnewbies.org [in Japanese]

• Get knowledge <== here

  • Development processes

    • ==> Development process materials

  • Plotted history of Linux releases

    • ==> google calendar

• Try anyway ==> try more and more

• Find someone who shares the same interests
• Do further
• Take off
• Find more friends

• <== I am talking here today!

* KernelNewbiesJapan

• http://jp.kernelnewbies.org/ [in Japanese]

• Japanese version of kernelnewbies
  • so that more people join the kernel development!
• It's wiki; anyone can edit it

* webresources

• http://jp.kernelnewbies.org/webresources [in Japanese]

• LWN

  • http://LWN.net

  • Kernel
    • Collecting topics on subsystems of the kernel
    • Past articles are archived by topics; convenient to retrieve later
  • News of the week relating to Linux are also collected
  • Status of the kernel development is summarized weekly

  • ==> You can get the fresh information you cannot find on web resources in Japan

  • Pages on distributions
    • Topics on the latest distributions
  • Jonathan said: Please point out if my English is difficult

• ChangeLog - KernelNewbies

  • You cannot find in any other place more summarized changes of the kernel
    • Changes in the past are collected too
• JF
  • httphttp://www.linux.or.jp/JF/ [in Japanese]
  • Publishes resources in Japanese
  • Translation of important documentation
    • "Documentation" of kernel translated into Japanese, etc.
  • Documentation on how to develop kernel published
    • Coding style, references
    • How to post patches
    • How to manage projects
• Kernel mentors project

  • http://selenic.com/mailman/listinfo/kernel-mentors

  • Consulting site for those who have code but do not know how to do with it
    • Easy questions such as "Is this modification OK?"
    • Advice on where to send patches
    • Advice on coding rules
  • Should learn the manner of the community to send mail
    • Insert comments between citation
• LinuxHQ

  • http://www.linuxhq.com/

  • Collecting the latest kernel status
  • Links to the latest kernel patches at the top of page are conveninet

• ==> These can be a first step to begin kernel develpment

  • Try and use these web pages!!
• LKML
  • And you are to debut here some day
  • Sites above can help you to reach here
  • You can not read all messages
    • Read with Gmail
    • Select by subjects
    • Read smart
      • Judge by number of comments (you can see on the archive)
      • Read when you have free time
  • Begin from today skiming through monthly archive etc. -spinics

    • http://www.spinics.net/lists/kernel/

    • ==> Style with more indents as the thread gets deeper;

      • May be rather browsable archive, though too deep threads reach to the right end

* Development Process

• Overview of development process
  • When a new Linux kernel is released, a special two weeks time frame, merge window, is fixed
  • In this term, maintainers send their patches to Linus
    • Usually, these patches have been those in -mm
  • -rc1 is released two weeks later
    • After then, stability is pursued
  • This cycle is repeated for 4-5 weeks, and then get towards the next version
• Development term
  • Five versions were released in 2006; a release every 70-90 days
  • 100K-220K lines and 300-700 files modified in each release

    • ==> Far beyond the level a single company can update

• Main trees
  • 2.6.x kernel that Linux organizes
  • Andrew Morton's 2.6.x-mm
    • 3000-4000 patches are included as candidates
  • Subsystem trees
    • Kbuild, ACPI, Block, IA64, libata, network, ...
  • Stable kernel
    • Trees after bug fixed; 2.6.x.y

* Plotting development history

• Plotted releases on Google calendar
• Plotted release date of major trees
  • Colored and checked to see the distribution of -mm, -rc, releases
• With Google calender, you can count how many rc's between releases
  • About 7 or 8 rc's have been released between releases
  • -mm can also be checked in the same manner
• -mm's have been released about twice a week

  • ==> These data can be useful to estimate the workload to catch up with kernels in your company

• Tracking the status of STABLE kernels tells you status of bug fixes

  • ==> Can see how difficult it is to download a kernel and to keep maintaining the specific version privately

• It is rumored that Linux wants to release on Wednesday
  • LWN is said to be updated on Thursday accordingly
• Would like to share this calender at some timing
  • Is it possible to plot automatically when a release is notfied?

* Summary

• Keep required manners and etiquette in mind
  • Written in the Documentation of Linux kernel
    • Translation in Japanese is in JF; Read this
• Check the status on LWN
• Learn about kernel development cycles

# Q & A

• Which kernel should I use?
  • The latest STABLE is desirable to use;
    • check the changelog of the STABLE release and judge if it is necessary