How to Do Your Own Analysis of the Kernel Development

Talk at LinuxCon Europe 2013.

The development of the Linux kernel is a complex process performed by a large community of contributors. Fortunately, many details about both the process and the development community are captured in the information stored in the git repository. This presentation will show how the MetricsGrimore and vizGrimoire toolsets can be used to perform targeted analysis and visualizations of this information. In addition, the results of some specific studies performed with the tools will also be shown as an illustration of their capabilities and easy of use.

Transcript

1. How to Do Your Own Analysis of the Kernel
   Development
   Jesus M. Gonzalez-Barahona
   @jgbarah
   Bitergia
   GSyC/LibreSoft, Universidad Rey Juan Carlos
   Edinburgh, UK, October 23rd 2013
   (draft, work in progress)
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 1 / 45
   

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2. c 2012-2013 Bitergia
   Some rights reserved. This presentation is distributed under the
   “Attribution-ShareAlike 3.0” license, by Creative Commons, available at
   http://creativecommons.org/licenses/by-sa/3.0/
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 2 / 45
   

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3. Bitergia: analytics for your peace of mind
   Started operations in July 2012
   Builds on the experience of LibreSoft R&D group
   Offering professional products and services
   Focused on:
   Metrics dashboards about software development
   (including community metrics)
   Specific studies and reports
   (based on metrics and facts collection)
   http://bitergia.com
   http://blog.bitergia.com
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 3 / 45
   

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4. Free software is (in many cases) special
   Source code available
   Open development model (usually)
   Many details about the internals of the development
   process
   Intense use of tools for coordination
   Lots of information is tracked, and available
   Developers & users communities are important
   sustainability
   pooling of resources
   innovation
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 4 / 45
   

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5. Measuring, measuring, measuring
   Information about code,
   community, development
   can be retrieved, organized,
   analyzed
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 5 / 45
   

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6. Metrics-tracked processes
   Quantitative, objective data: facts, not opinions
   Specific questions can be answered
   Several areas of interest:
   Developers:
   Understanding, improving development processes
   Early detection of potential problems, bad smells
   Community:
   General activity, contributions
   Long-term sustainability, evolution, reaction to issues
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 6 / 45
   

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7. But data has to be extracted, mined...
   Data lives in repositories not always designed to release all
   their data easily:
   tools are needed to retrieve and extract it
   Data includes many complexities and details
   tools are needed to filter, organize it
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 7 / 45
   

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8. But data has to be analyzed, visualized...
   Casual observation is not enough, analysis is needed:
   tools are needed
   for statistical and other kinds of analysis
   Analysis is not enough, visualization may help:
   tools are needed for interactive visualization
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 8 / 45
   

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9. The MetricsGrimoire approach
   Set of tools specialized in retrieving information from
   different kinds of repositories. Among them:
   CVSAnalY: source code management (CVS,
   Subversion, git, etc.)
   Bicho: issue tracking systems (Bugzilla, Jira,
   SourceForge, Allura, Launchpad, etc.)
   MLStats: mailing lists (mbox files, Mailman archives,
   etc.)
   Store all the information in SQL databases with similar
   structure
   http://metricsgrimoire.github.io
   Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 9 / 45
   

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10. The vizGrimoire approach
    Set of tools for analyzing and visualizing data produced by
    MetricsGrimoire:
    vizGrimoireR: R package for analysis and producing
    JSON files
    vizGrimoireJS: JavaScript library for visualizing JSON
    files
    Several dashboards: based on vizGrimoireJS
    From SQL to JSON to visualization
    http://vizgrimoire.github.io
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 10 / 45
    

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11. The *Grimoire combination
    Visualization
    Parsing Actions
    Retrieval Process
    Retrieval Process
    (data mining tools)
    ...
    ...
    DB DB DB
    SCM BTS X
    Visualization
    Parsing Actions
    Retrieval Process
    Parsing Actions
    (R and Python scripts)
    ...
    ...
    DB DB DB
    JSON JSON JSON
    Visualization
    Parsing Actions
    Retrieval Process
    Visualization
    (HTML, CSS and JS)
    ...
    ...
    JSON JSON JSON
    HTML HTML HTML
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 11 / 45
    

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12. MetricsGrimoire: CVSAnalY
    Browses an SCM repository producing a database
    with:
    All metainformation (commit records, etc.)
    Metrics for each release of each file
    Also produces some tables suitable for specific analysis
    Multiple SCMs: CVS, svn, git (Bazaar, Mercurial
    through git)
    Whole history in the database, it’s possible to rebuild
    the files tree for any revision
    Tags and branches support
    Option to save the log to a file while parsing
    Extensions system, incremental capabilities
    Multiple database system support (MySQL and
    SQLite)
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 12 / 45
    

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13. MetricsGrimoire: CVSAnalY extensions
    Extension: a “plugin” for CVSAnalY
    Add information to the database, based in the
    information in the database and maybe the repository
    Usually: new tables for specific studies
    Simple example: commits per month per commiter
    Extensions add one or more tables to the database but
    they never modify the existing ones
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 13 / 45
    

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14. MetricsGrimoire: CVSAnalY extensions
    Some examples:
    FileTypes: adds a table containing information about
    the type of every file in the database (code,
    documentation, i18n, etc.)
    Metrics: analyzes every revision of every file
    calculating metrics like sloc and complexity metrics
    (mccabe, halstead). It currently supports metrics for
    C/C++, Python, Java and ADA.
    CommitsLOC: adds a new table with information
    about the total lines added/removed for every commit
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 14 / 45
    

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15. MetricsGrimoire: Bicho
    Parsing issue tracking systems
    Results stored in a MySQL database
    Information about each issue (ticket), and its
    modifications
    Currently it supports:
    SourceForge (HTML parsing)
    Bugzilla: GNOME, KDE, others
    Jira, Allura, Launchpad, GitHub, RedMine (API)
    Incremental
    Supports Gerrit as well (code review)
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 15 / 45
    

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16. MetricsGrimoire: MailingListStats
    Parses mbox information (RFC 822)
    Deals with Mailman archives
    Stores results (headers, body) in a MySQL database:
    Sender, CCs, etc.
    Time / Date
    Subject
    ...
    Incremental
    Can store multiple projects in a single database
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 16 / 45
    

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17. vizGrimoireR & vizGrimoireJS
    Once information is retrieved, and is in a format suitable
    for querying:
    it can be queried directly in the database
    it can be analyzed from R
    it can be filtered, manually inspected, improved
    it can be combined, cross-analyzed
    it can be visualized
    Milking the databases, producing dashboards
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 17 / 45
    

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18. Now...
    ...howto for the Linux kernel
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 18 / 45
    

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19. Data sources used
    Git snapshot with changes since 1992,
    by Yoann Padioleau
    reliable about individual changes since 2002)
    updated (git pull) up to September 2013
    http://archive.org/details/git-history-of-linux
    git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/
    linux.git
    Gmane linux-kernel mailing list
    http://dir.gmane.org/gmane.linux.kernel
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 19 / 45
    

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20. Running the tools: getting MetricsGrimoire
    Get source code from GitHub repositories and
    follow instructions
    ...or...
    run metricsgrimoire-setup.py
    https://github.com/VizGrimoire/VizGrimoireR/blob/master/
    misc/metricsgrimoire-setup.py
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 20 / 45
    

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21. Running the tools: CVSAnalY (git)
    Get the git repo with historic information
    Run CVSAnalY to populate cvsanalydb database
    wget http://archive.org/download/
    git-history-of-linux/full-history-linux.git.tar
    tar xvf full-history-linux.git.tar
    cd full-history-linux
    git pull
    [Create databases cvsanalydb]
    cvsanaly2 -u user -p XXX -d cvsanalydb \
    --extensions=FileTypes,CommitsLOC .
    [From vizGrimoireR/misc, >5,000 dup ids found]
    unifypeople.py -u user -p XXX -d cvsanalydb
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 21 / 45
    

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22. Running the tools: MLStats (mailing list)
    [From vizGrimoireR/examples/linux]
    get-gmane-archive.sh
    mlstats --db-user=user --db-password=XXX \\
    --db-admin-user=adminuser --db-admin-password=XXX \\
    --db-name=mlstatsdb \\
    mail_dir
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 22 / 45
    

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23. Running the tools: Producing a basic dashboard
    Installation of vizGrimoireR as package for R
    https://github.com/VizGrimoire/VizGrimoireR/wiki
    Produce all the files for the dashboard
    [ in vizGrimoireR directory, run R scripts to produce JSON ]
    vizGrimoireJS/run_scripts-linuxkernel.sh
    [ get HTML (JavaScript, HTML, CSS) files for dashboard ]
    git clone git@github.com:VizGrimoire/VizGrimoireJS.git \
    linux-dashboard
    cd linux-dashboard
    git checkout linux
    [ copy JSON files produced above ]
    cp ../json/* ./data/json
    Export the directory via HTTP
    Access it your favorite web browser
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 23 / 45
    

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24. Basic dashboard
    Limited functionality, work in progress
    http://bitergia.com/public/previews/2013_10_linux/browser/
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 24 / 45
    

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25. Basic dashboard (git)
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 25 / 45
    

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26. Basic dashboard (mailing list)
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 26 / 45
    

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27. A more complete dashboard: MediaWiki
    http://korma.wmflabs.org/
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 27 / 45
    

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28. Case: Activity per directory in git repository
    Three CVSAnalY tables involved:
    scmlog: metadata for each commit (author, date, ...)
    actions: metadata for each action on a file (file,
    commit, ...)
    file links: metadata for each file (name, path, ...)
    Group all actions involving files under a certain
    subdirectory,
    calculate number of actions and (distinct) authors
    involved
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 28 / 45
    

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29. Size (LOC) per subdirectory
    code
    arch/alpha
    arch/arm
    arch/ia64
    arch/m68k
    arch/mips
    arch/powerpc
    arch/s390
    arch/sh
    arch/tile
    arch/x86
    drivers/acpi
    drivers/gpu
    drivers/infiniband
    drivers/input
    drivers/isdn
    drivers/md
    drivers/media
    drivers/mfd
    drivers/mtd
    drivers/net
    drivers/pinctrl drivers/s390
    drivers/scsi
    drivers/staging
    drivers/tty
    drivers/usb
    drivers/video
    fs/btrfs
    fs/cifs fs/ext4
    fs/jfs
    fs/nfs
    fs/nfsd
    fs/ocfs2
    fs/xfs
    include/linux
    net/core
    net/ipv4
    net/ipv6
    net/netfilter
    sound/pci
    sound/soc
    arch
    block
    crypto
    drivers
    fs
    include
    ipc
    kernel
    lib
    mm
    net scripts
    security
    sound
    tools
    cloc –csv –skip-uniqueness –by-file .
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 29 / 45
    

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30. Changes per directory
    actions
    arch
    block
    Documentation
    drivers
    fs
    include
    init
    ipc
    kernel
    lib
    mm
    net
    scripts
    security
    sound
    tools virt
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 30 / 45
    

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31. Changes per directory: more detail
    actions
    arch/alpha
    arch/arm
    arch/i386
    arch/ia64
    arch/mips
    arch/powerpc
    arch/ppc
    arch/s390
    arch/sh
    arch/sparc
    arch/um
    arch/x86
    drivers/acpi
    drivers/block
    drivers/char
    drivers/gpu drivers/ide
    drivers/input
    drivers/media
    drivers/net
    drivers/scsi
    drivers/staging
    drivers/tty
    drivers/usb drivers/video
    fs/btrfs
    fs/cifs
    fs/gfs2
    fs/nfs
    fs/nfsd
    fs/xfs
    include/linux
    net/inet
    net/ipv4
    net/ipv6
    net/mac80211
    arch
    block
    Documentation
    drivers
    fs
    include
    init
    ipc
    kernel
    lib
    mm
    net
    scripts
    security
    sound
    tools
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 31 / 45
    

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32. Changes per directory: color is number of authors
    actions
    authors
    0 500 1000 1500 2000 2500 3000 3500 4000
    arch/arm arch/i386
    arch/ia64
    arch/m68k
    arch/mips
    arch/powerpc
    arch/ppc
    arch/sh
    arch/sparc arch/um
    arch/x86
    arch/x86_64
    drivers/acpi
    drivers/char
    drivers/gpu
    drivers/i2c
    drivers/ide
    drivers/media
    drivers/mtd
    drivers/net
    drivers/scsi
    drivers/staging
    drivers/usb
    drivers/video
    fs/cifs
    fs/gfs2
    fs/nfs
    fs/nfsd
    fs/xfs
    include/linux
    include/net
    net/inet
    net/ipv4 net/ipv6
    net/sctp
    sound/soc
    arch
    drivers
    fs
    include
    kernel
    net
    sound
    tools
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 32 / 45
    

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33. Changes per directory: color is density of authors
    actions
    authors per actions
    0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
    arch/arm arch/i386
    arch/ia64
    arch/m68k
    arch/mips
    arch/powerpc
    arch/ppc
    arch/sh
    arch/sparc arch/um
    arch/x86
    arch/x86_64
    drivers/acpi
    drivers/char
    drivers/gpu
    drivers/i2c
    drivers/ide
    drivers/media
    drivers/mtd
    drivers/net
    drivers/scsi
    drivers/staging
    drivers/usb
    drivers/video
    fs/cifs
    fs/gfs2
    fs/nfs
    fs/nfsd
    fs/xfs
    include/linux
    include/net
    net/inet
    net/ipv4 net/ipv6
    net/sctp
    sound/soc
    arch
    drivers
    fs
    include
    kernel
    net
    sound
    tools
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 33 / 45
    

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34. Changes per directory: 2002
    actions
    authors per actions
    0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
    arch/alpha
    arch/arm
    arch/i386 arch/ia64
    arch/m68k
    arch/mips
    arch/powerpc
    arch/ppc
    arch/ppc64
    arch/sh
    arch/sparc64
    arch/um
    arch/x86
    arch/x86_64
    drivers/acpi
    drivers/block
    drivers/char
    drivers/ide
    drivers/input
    drivers/isdn
    drivers/media
    drivers/net
    drivers/scsi
    drivers/usb
    drivers/video
    fs/jfs
    fs/nfsfs/nfsd
    fs/ntfs
    fs/xfs
    include/asm−x86
    include/linux
    net/inet
    net/ipv4 net/sctp
    sound/oss
    sound/pci
    arch
    block
    drivers
    fs
    include kernel
    lib
    net
    sound
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 34 / 45
    

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35. Changes per directory: 2013
    actions
    authors per actions
    0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
    arch/arc
    arch/arm
    arch/i386
    arch/mips
    arch/powerpc
    arch/s390
    arch/tile
    arch/x86
    drivers/acpi
    drivers/char
    drivers/dma
    drivers/gpu
    drivers/media
    drivers/net
    drivers/scsi
    drivers/spi
    drivers/staging
    drivers/tty
    drivers/usb
    fs/btrfs
    fs/ceph
    fs/cifs
    fs/ext4
    fs/f2fs
    fs/nfs
    fs/xfs
    include/linux
    net/ipv4
    arch
    Documentation
    drivers
    fs
    include
    kernel
    net
    sound tools
    virt
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 35 / 45
    

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36. Case: experience of developers
    Different ids for same developers have to be merged
    simple heuristics
    > 5, 000 dup ids for about 10,000 devels
    https://github.com/VizGrimoire/VizGrimoireR/blob/master/
    misc/unifypeople.py
    Three CVSAnalY tables involved:
    scmlog: metadata for each commit (author, date, ...)
    people: metadata for ids corresponding to developers
    upeople: ‘unified’ ids for developers
    Calculate ‘age in project’ for active developers at a
    certain spot in time, grouping them by
    ‘generations’
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 36 / 45
    

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37. Experience: demography prydamid (git)
    0
    4
    8
    12
    0 100 200 300
    Number of developers
    Age
    Generations (active authors of commits), March 1st, 2013
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 37 / 45
    

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38. Experience: demography prydamid (git)
    0
    4
    8
    12
    0 100 200 300 400
    Number of developers
    Age
    date
    2003−03−01
    2005−03−01
    2007−03−01
    2009−03−01
    2011−03−01
    2013−03−01
    0
    4
    8
    12
    0 100 200 300 400
    Number of developers
    Age
    date
    2003−03−01
    2005−03−01
    2007−03−01
    2009−03−01
    2011−03−01
    2013−03−01
    Comparison for pyramids every two years
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39. Experience: demography prydamid (git)
    2003−03−01 2005−03−01 2007−03−01
    2009−03−01 2011−03−01 2013−03−01
    0
    4
    8
    12
    0
    4
    8
    12
    0 100200300400 0 100200300400 0 100200300400
    Number of developers
    Age (quarters)
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 39 / 45
    

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40. Experience: demography prydamid (git)
    3D version of pyramids every two years
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 40 / 45
    

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41. Case: where do developers work?
    Study on mailing list:
    assumption: time zones of mail tools are correct
    time zones correspond roughly to geographical areas
    http:
    //en.wikipedia.org/wiki/Time_zone#UTC_offsets_worldwide
    Americas: GMT-8 to GMT-2 (US/Canada: -8 to -4)
    Europe/Africa/Middle East: GMT to GMT+5
    East Asia/Australia: GMT+8 to GMT+11
    All the info in one MLStats table:
    messages: main headers of each message
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 41 / 45
    

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42. Timezone origin of messages
    0e+00
    1e+05
    2e+05
    −10 −5 0 5 10
    Timezones (relative to GMT)
    Messages
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43. Timezone origin of messages (2002, 2007, 2012)
    0
    5000
    10000
    15000
    −10 −5 0 5 10
    Messages
    0
    10000
    20000
    30000
    −10 −5 0 5 10
    Messages
    0
    10000
    20000
    30000
    −10 −5 0 5 10
    Messages
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 43 / 45
    

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44. Takeaways
    Run MetricsGrimoire on the repositories,
    get your own databases
    Use our databases,
    use vizGrimoire to run your own analysis,
    produce your own visualizations
    Use our analysis scripts,
    modify them for your own purposes
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 44 / 45
    

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45. This is the end
    Have you learned something
    useful?
    [I would love to know what interested you the most]
    [...and the least]
    Code for the examples on the Linux kernel: https://github.com/
    VizGrimoire/VizGrimoireR/tree/master/examples/linux
    Databases: http://bitergia.com/public/previews/2013_10_linux/
    browser/data/db
    Jesus Gonzalez-Barahona (Bitergia/URJC) Your Own Analysis of the Kernel Development LinuxCon Europe 2013 45 / 45
    

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