Status of Embedded Linux

CE Worgroup Work Update

May 2011 Tim Bird Architecture Group Chair LF CE Workgroup

Outline

• • • • Status of merger with Linux Foundation CELF contract work • Review of 2010 work • Plan for 2011 work Conferences • Other meetings Other initiatives

Merger Status

Merger with Linux Foundation

• • • • Merger was completed in January 2011 Some final legal details still being wrapped up CELF is now the Linux Foundation “CE Workgroup” Now starting to utilize Linux Foundation infrastructure – Should mean it's easier for non-members to participate in CE WG projects!

Contract Work 2010

CELF Contract Work 2010

• • • • • • • • Bootchart and smemcap in busybox Function-sections YAFFS2 mainline effort SquashFS enhancements U-Boot ARM enhancements Trace format standard Kexecboot enhancements Flash filesystem testing

Bootchart and smemcap support in busybox Smemcap applet

• • • • Bootchart applet - Captures bootchart data • See http://elinux.org/Japan_Technical_Jamboree_33 • See http://elinux.org/Bootchart#BusyBox Smemcap applet – captures smem data • Data can be moved to host for analysis and visualization Contractor: Denys Vlasenko Status: Completed • Applets are available in busybox mainline

Function-sections

• • • Description: • Add support to Linux kernel for gcc dead code removal –ffunction sections option, to shrink kernel size by improving • • Puts each function in its own linker section Required a big section rename in kernel Contractor: Denys Vlasenko Status: • Most parts mainlined • Waiting to resolve linker issues for weird symbols on PARISC • Effort stalled – need to finish it

Mainline YAFFS2

• • • • Description: • YAFFS2 is a popular NAND flash filesystem • Was used by Android in many devices • Add support for YAFFS2 to mainline kernel Contractor: Aleph One Ltd Google Co-Sponsored this project Status: • 3 mainline attempts made, but hit some barriers • Currently stuck on some locking issues • Outlook for mainline acceptance is uncertain

SquashFS LZMA/LZO Support

 Description:  LZMA and LZO support  Contractor: Phillip Lougher  Status:   LZMA work was submitted, and was in Linux-next, but got rejected LZO work (contributed by LGE) was mainlined!!

ARM improvements in U-boot

• • • Description: • Improve aspects of U-boot for ARM • Allow relocating bootloader • Turn caches on for faster booting Contractor: Wolfgang Denx Status: • Work was completed and mainlined in U-Boot

U-Boot Results: Test

U-boot image size Copy 32M NOR -> RAM iminfo of 1.2 MiB image bootm of 1.2 MiB gz image Bootm of 0.8 MiB lzma image Bootm of 1.6 MiB lzo image 191K 7.0s

0.5s

5.4s

17,1s 3.2s

Old (icache) New (i+d cache

204K 6.5s

0.1s

0.5s

1.5s

0.2s

Improvement

x 1.07

x 5.0

x 10.8

x 11.4

x 16.0

• Limit for boot time into app code is 5s so U-boot image compression was not possible. But now it is.

• Results from Matthias Weißer on Aug 5, 2010 • See http://article.gmane.org/gmane.comp.boot-loaders.u boot/82079

Trace format standard

• • • Description: • Create a singled trace format standard for the embedded industry Contractor: Efficios (Matthieu Desnoyers) Status: • Standard (Common Trace Format) was created • See http://www.efficios.com/ctf • BabelTrace trace conversion library • Proof of concept conversion implementation – Can convert kernel messages with timestamps to CTF and back to text

Kexecboot improvements

 Description:  Improve user interface and supported storage devices for kexecboot   Contractor: Yuri Bushmelev Status:   Interface has been enhanced Work on reading other storage devices was completed

Flash filesystem testing

 Description:  Measure different flash filesystems for comparisons   Contractor: Free Electrons Status:  Results were shown at ELC Europe 2010

Contract Work 2011

Open Project Proposal

• • • • • Project ideas were collected in Dec. 2010 and Jan. 2011 Bids were solicited in March – – Architecture Group approved projects in April 11 projects approved out of 28 Still have budget for more projects Contracts are being finalized now Have a good list, but would like more proposals from CE WG/LF members

Contract Work 2011

• • • • • Improve UBIFS mount time Mainline Android kernel features Mainline fast symbol resolution Work on Linux tiny patches Support read-only block filesystems on flash devices

Contract Work 2011 (cont.)

• • • • • • eLinux wiki content for kernel trace and debug Mainline the watchdog framework Flash filesystem testing Extend bluetooth stack with Remote SIM Access protocol Mainline Device Firmware Upgrade (DFU) code in U-Boot Solicit project proposals throughout year

Improve UBIFS mount time

• • • Description: • Add logging or checkpointing to UBI to avoid bad block scan of whole device on UBI attach Contractor: Linutronix (Thomas Gleixner) Status: • Contract almost finished

Mainline Android kernel features

• • • Description: • Add a single Android feature (logger) to mainline, as a pilot project for 3 rd party mainlining of Android code • Longterm goal is to mainline as much of Android as possible, to reduce difference and allow for easier “unified distro kernel” • Kernel that can run Ubuntu, Android, etc.

Contractor: have interest from Alessio Bogani Status: • Still working on project plan and bid

Mainline fast symbol resolution

• • • Description: • Change symbol lookup to use binary search instead of linear scan • Speeds up module loading Contractor: Alessio Bogani Status: • Patches are in linux-next

Work on Linux tiny patches

 Description:    Revive Linux-tiny patch set Forward-port patches to latest kernel Add more patches to improve kernel configurability   Contractor: We Zhanjin Status:  Contract ready to sign

Support read-only block filesystems on flash media

   Description:   Write block emulation layer to support read-only filesystems on top of MTD layer in kernel Will allow Squashfs to be used on raw NAND flash media Contractor: Phillip Lougher Status:  Contract in progress

eLinux wiki content for trace and debug

 Description:  Collect content on kernel trace and debug techniques and publish on eLinux wiki   Contractor: Peter Huewe Status:  Contract ready to sign

Mainline the watchdog framework

 Description:     Mainline the watchdog framework Original framework was written by Alan Cox and others Provides a generalized watchdog mechanism Should provide easier method to add watchdogging to drivers and the kernel going forward   Contractors: Wolfram Sang and Wim van Sebroeck Status:  Contract ready to sign

Flash filesystem testing

   Description:   Perform mount and runtime performance tests on multiple flash filesystems, for each new kernel release Publish results on eLinux wiki Contractor: Free Electrons Status:  Contract ready to sign

Extend bluetooth stack with Remote SIM Access protocol

   Description:   Allows for Linux bluetooth and telephony stack to utilize SIM in external device for operation Primary use case is for Linux-based in-car system to utilize SIM in mobile device for calls, etc.

Contractor: ProFusion Status:  Contract almost complete

Mainline Device Firmware Upgrade (DFU) code in U-Boot

   Description:   Device Firmware Upgrade (DFU) is an industry standard system for upgrading and manipulating firmware in embedded devices Add support for this protocol to U-Boot mainline Contractor: Stefan Schmidt Status:  Contract ready to sign

Solicit project proposals throughout the year

 Description:   CE Workgroup will continue to maintain the Project Proposal wiki page, and will continue accepting ideas and proposals for contract work through 2011 This will allow ideas to come in as they are generated and relevant, instead of accumulating them throughout the year   Contractor: Bill Traynor Status:  Contract ready to sign

Conferences

Conferences

 Past – ELC 2011 and Android Builders Summit • Videos just announced – see wiki page • Kato-san will give a report later today  Future    LinuxCon Japan – June 1-3, Yokohama ELC Europe 2011 – Oct 26-28, Prague LinuxCon Brazil – Nov 17-18, Sao Paulo  Continuing Japan Jamborees  ELC and Android Builders Summit in 2012  See http://events.linuxfoundation.com/ and http://elinux.org/events

Embedded Linux Summit

• • • • Invitation-only event to discuss embedded issues between key industry and community leaders Was held September 30, 2010 in Tokyo and October 26 in Cambrige, UK Similar to other mini-summits, but with focus on embedded issues Leading up to kernel summit in November – Has lead to several initiatives – Big one was longterm kernel branch, maintained by Andi Kleen

Android mainline BOF

• • • • Invitation-only event to discuss Android mainline issues Was held April 14 in San Francisco – Linaro, CE WG, Google and Qualcomm attended Very good discussion about what different members of the “Android/Linux ecosystem” could do to coordinate work and mainline Android technologies CE WG “mainline Android logger” project is a result of this meeting

Other Initiatives

eLinux Wiki

• • • • • • • http://elinux.org/ Wikipedia for embedded Linux developers Very good for

some

technical areas I have been working on Android Portal section of site Recently moved to OSU Open Source Lab hosting Promotion • Contest – just finished best editor contest!

Please use it and post stuff

Hardware Donations

• • CELF donates hardware for some open source developers • example: Board for BKL removal work E-mail me if you need hardware for a project that you think CELF would be interested in

Thanks!