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Embedded Linux Embedded

VIEWS: 12 PAGES: 22

									                 Embedded Linux BOF

                             Tim Bird
                 Software Engineer, Sony Electronics
                 Chair, CE Linux Forum Architecture
                               Group

March 12, 2012              CE Linux Forum Members     1
                                  Confidential
                 Embedded Linux Stuff
•   Year in Review
•   Shameless plug
•   Embedded Linux wiki
•   Lightning talks




March 12, 2012         CE Linux Forum Members   2
                             Confidential
                  Year in Review
•   Real-time
•   Size
•   Bootup Time
•   Audio/Video/Graphics
•   Security
•   Power Management
•   Mobile Phone
•   Processor support
•   Tools

March 12, 2012       CE Linux Forum Members   3
                           Confidential
                           Realtime
• hrtimers (2.6.18?)
     – clock sources (2.6.18)
     – HR timer API
           • http://lwn.net/Articles/167315/
     – ktimers explanation:
      • http://lwn.net/Articles/152436/
• Generic IRQ (2.6.18)
• Tickless Idle coming

March 12, 2012            CE Linux Forum Members   4
                                Confidential
                          Rt-Preempt
• Mainline status
     – Most stuff in, “only” need:
           • sleeping spinlocks
           • threaded IRQs
• Priority Inheritance (2.6.18)
     – http://lwn.net/Articles/177838/
• Latency tracer

March 12, 2012            CE Linux Forum Members   5
                                Confidential
                                   Size
•   Linux-tiny
•   Squashfs
•   Inode Slimming
•   Unit-at-a-time compilation
• Size Testing
     – Bloatwatch
     – Config size testing



March 12, 2012               CE Linux Forum Members   6
                                   Confidential
                 Linx-tiny mainlining
•   small-8023.patch
•   fs_open-inlines.patch
•   inode-inlines.patch
•   fslocks-inline.patch
•   bloat-o-meter.patch
•   no-doublefault.patch
•   no-elf-core.patch
•   slob.patch
•   remove-vm86.patch
•   uid16.patch
March 12, 2012         CE Linux Forum Members   7
                             Confidential
             Inode Slimming Patches
• brand new
     – july 3 - Ted Tso (not mainlined yet)
• Tips:
     – Ted Tso - if you want to save memory taken up
       by in-core inodes, the first thing you should do
       is disable the debugging options; they are
       responsible for a huge amount of bloat in the
       VFS inode structure

March 12, 2012       CE Linux Forum Members               8
                           Confidential
         Unit-at-a-time Compilation
• Ingo Molnar patch to utilize gcc 4 unit-at-a-
  time compilation
     – http://lkml.org/lkml/2005/12/28/68
     – http://lwn.net/Articles/165354/
• inline reduction
     – New _always_inline_ attribute:
           • http://lwn.net/Articles/167315/
           • http://lwn.net/Articles/165354/
March 12, 2012            CE Linux Forum Members   9
                                Confidential
                   Size Testing
• Bloatwatch
     – http://testlab.celinuxforum.org/...
• Config size testing
     – Presentation at CELF Project BOF




March 12, 2012        CE Linux Forum Members   10
                            Confidential
                   Security
• AppArmour
     – Lighter than SELinux
     – Good enough for embedded work??
• LSM in peril…




March 12, 2012     CE Linux Forum Members   11
                         Confidential
                 Bootup Time
• XIP - Execute in Place
     – Old info: http://lwn.net/Articles/135472/
     – XAFS - new file system specifically for XIP
        • Jared Hulbert (Intel) posted for comments:
            – http://lwn.net/Articles/182337/




March 12, 2012       CE Linux Forum Members            12
                           Confidential
                 Power Management
• User-space software suspend
• Latest kerfluffle over suspend phases
     – Linus has posted a new patch, showing his method.
     – See lwn.net: http://lwn.net/Articles/189467
• Linux PM summit
     – http://lwn.net/Articles/181687
     – Main issues: See PM BOF 19:00 Room A



March 12, 2012         CE Linux Forum Members              13
                             Confidential
                 Audio/Video/Graphics
• Big direct rendering update
     – http://lwn.net/Articles/167315/
• New CELF AVG Spec. (2.0)
     – DirectFB, ALSA, OpenGL/ES, UHAPI




March 12, 2012        CE Linux Forum Members   14
                            Confidential
                 Mobile phone stuff
• CELF specification still in-progress
• More organizations than you can
  “shake a stick at”:
     –   CELF MPPWG
     –   OSDL MLI
     –   LIPS
     –   “the new one”

March 12, 2012       CE Linux Forum Members   15
                           Confidential
                       Tools
• Tracing
     – LTTgn just recently re-added lots of
       architecture support
     – LTTng, KFT, LKST - See Tracing BOF, 19:00
       Room D
• Memory Leak Tracker
• Compilers
     – Thumb support
March 12, 2012     CE Linux Forum Members      16
                         Confidential
                        Other
• Function re-ordering
     – http://lwn.net/Articles/173657/
• GPL3
     – “Nothing to see here, move along…




March 12, 2012       CE Linux Forum Members   17
                           Confidential
    News from the Kernel Summit
•   LSM stays for now
•   suspend/resume still messed up
•   no transparent super-pages
•   Kernel leaders sympathetic to size issue
•   other stuff??



March 12, 2012     CE Linux Forum Members      18
                         Confidential
                  Shameless plug
• CELF Project BOF
     –   Friday night, 7:00 pm, Les Suites
     –   CELF Test Lab demo
     –   Config size testing
     –   CABI CPU resource reservation
     –   Japan Jamboree update
     –   Technical showcase

March 12, 2012         CE Linux Forum Members   19
                             Confidential
                 Embedded Linux Wiki
• Place to store info on embedded Linux
• Starter material from CELF wiki
• Paid maintenance, to avoid wiki rot
     – CELF may fund, if plan looks good and there’s
       community interest
• BOF this week to discuss


March 12, 2012        CE Linux Forum Members       20
                            Confidential
                 Lightning talks
• 2 minutes (max)
     – what are you doing? / what is the issue? when
       will you publish!?
     – make it quick and to-the-point
     – where to go for more info…




March 12, 2012       CE Linux Forum Members            21
                           Confidential
                 Lightning topics




March 12, 2012      CE Linux Forum Members   22
                          Confidential

								
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