https://wiki.linaro.org/projects/big.LITTLE.MP
Work Items for functional completion: https://wiki.linaro.org/projects/big.LITTLE.MP/WorkItems
Main Project page: https://launchpad.net/linaro-big-little-system
Development ============
1. big.LITTLE IKS
IKS snapshot: git://git.linaro.org/landing-teams/working/arm/kernel.git
More information: http://lists.linaro.org/pipermail/linaro-dev/2013-May/015882.html
Also the latest Linaro 13.05 release contains big.LITTLE release with IKS code integrated. By default MP is used (IKS is off). To enable IKS:
echo 1 > /sys/kernel/bL_switcher/active
2. big.LITTLE MP
There are two branches, which are functionally equivalent - they tweak the scheduler to select the right processes to move to the A15 and try to decrease power consumption while maintaining performance.
* A Reference (stable) big.LITTLE MP patchset (merged with linux-linaro):
https://git.linaro.org/gitweb?p=arm/big.LITTLE/mp.git%3Ba=shortlog%3Bh=refs/...
Recommended to be used for testing.
* And an upstream (work in progress) big.LITTLE MP patchset:
https://git.linaro.org/gitweb?p=arm/big.LITTLE/mp.git%3Ba=shortlog%3Bh=refs/...
Being worked on in order to achieve the performance/power numbers of the reference one. Upstream discussion is ongoing.
* Documentation:
Code flow is already covered by several LWN articles. See https://wiki.linaro.org/WorkingGroups/PowerManagement/Doc/ in the Articles section. We will provide a tuning guide once we have reached agreement upstream.
* Automated benchmarking code is ready:
- A python script to download LAVA bundle and extract results and populate results on to given Google spreadsheet is complete and is in use. Some workarounds are needed for automatic pushing of results to spreadheet.
Blueprint Updates ------------------
* https://blueprints.launchpad.net/linaro-big-little-system/+spec/big-little-m...
Ongoing work.
* https://blueprints.launchpad.net/linaro-big-little-system/+spec/small-task-p...
- new version is being worked on
* https://blueprints.launchpad.net/linaro-big-little-system/+spec/cpu-hot-plug...
- done.
* https://blueprints.launchpad.net/linaro-big-little-system/+spec/sched-cooper...
- Postponed. Priorities are to be re-evaluated.
QA ==
big.LITTLE MP LAVA Dashboard http://validation.linaro.org/lava-server/dashboard/image-reports/linaro-andr...
Testing (week 22):
sched_tests.git #Cases #Run Pass Fail Absolute pass rate Regression 20 19 19 0 100 % mpbasicsuite 14 10 10 0 100 % mpcoresuite 10 6 6 0 100 % mpextendedsuite 20 10 7 3 70 % mploadbalance 2 2 2 0 100 %
http://lists.linaro.org/pipermail/linaro-dev/2013-May/016006.html
Bugs: https://bugs.launchpad.net/linaro-big-little-system/+bugs?field.tag=bl-mp
Highlight: Bug 1166246 - Lockup on post 3.9 IKS kernel
- can be hardware or software bug, investigation continues. - seems to be related to MMC being in use (switching to USB stick can be used as a reliable workaround).