Embedded Linux BOF Tim Bird Software Engineer Sony
Embedded Linux BOF Tim Bird Software Engineer, Sony Electronics Chair, CE Linux Forum Architecture Group CE Linux Forum Members Confidential 1
Embedded Linux Stuff • • Year in Review Shameless plug Embedded Linux wiki Lightning talks CE Linux Forum Members Confidential 2
Year in Review • • • Real-time Size Bootup Time Audio/Video/Graphics Security Power Management Mobile Phone Processor support Tools CE Linux Forum Members Confidential 3
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 CE Linux Forum Members Confidential 4
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 CE Linux Forum Members Confidential 5
Size • • Linux-tiny Squashfs Inode Slimming Unit-at-a-time compilation • Size Testing – Bloatwatch – Config size testing CE Linux Forum Members Confidential 6
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-vm 86. patch uid 16. patch CE Linux Forum Members Confidential 7
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 CE Linux Forum Members Confidential 8
Unit-at-a-time Compilation • Ingo Molnar patch to utilize gcc 4 unit-at-atime 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/ CE Linux Forum Members Confidential 9
Size Testing • Bloatwatch – http: //testlab. celinuxforum. org/. . . • Config size testing – Presentation at CELF Project BOF CE Linux Forum Members Confidential 10
Security • App. Armour – Lighter than SELinux – Good enough for embedded work? ? • LSM in peril… CE Linux Forum Members Confidential 11
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/ CE Linux Forum Members Confidential 12
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 CE Linux Forum Members Confidential 13
Audio/Video/Graphics • Big direct rendering update – http: //lwn. net/Articles/167315/ • New CELF AVG Spec. (2. 0) – Direct. FB, ALSA, Open. GL/ES, UHAPI CE Linux Forum Members Confidential 14
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” CE Linux Forum Members Confidential 15
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 CE Linux Forum Members Confidential 16
Other • Function re-ordering – http: //lwn. net/Articles/173657/ • GPL 3 – “Nothing to see here, move along… CE Linux Forum Members Confidential 17
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? ? CE Linux Forum Members Confidential 18
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 CE Linux Forum Members Confidential 19
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 CE Linux Forum Members Confidential 20
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… CE Linux Forum Members Confidential 21
Lightning topics CE Linux Forum Members Confidential 22
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