EAS Development for Mainline Linux

EAS development for mainline Linux takes place on LKML and Linaro eas-dev mailing lists where proposed patches are discussed with the community.

Arm now provides a pre-integrated version of latest EAS patches for mainline, for upstream development use.  eas/next is a moving integration branch tracking tip:sched/core and adding the latest versions of EAS related patch sets targeted at the mainline kernel. The patches may already be under discussion on relevant open source mailing lists or waiting here while its dependencies get resolved and merged upstream.

The integration branch comes as is with minimum testing. The intention is to have a single branch containing the full EAS picture for mainline Linux kernel developers interested in tracking progress.

NOTE this EAS integration branch is not suitable for product development. For product, please use the AOSP EAS product codeline.

Source code

EAS-for-mainline integration branches are made available regularly on:

        git://linux-arm.org/linux-power.git

Update 11-Nov-2017:  Arm increases frequency of integrations to once every 2 weeks to more closely track mainline changes and improve testing.

Update 19-Jan-2018:  Arm runs Lisa tests (generic and load_tracking) against each EAS integration from now on.

  • eas/next/integration_20180119

    Tree:

    integration_20180119

    Integration base (git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core) available at:

    integration_20180119_base

    Platform support:

    Arm TC2, Arm Juno r2, Hikey620, Hikey960

    New changes:

    Added cgroup related load-tracking test cases.

    Main features:

    • EAS core patches that make energy-aware task placement decisions.
    • Misfit task, i.e. forcing migration of running tasks that do not fit on the CPU they are currently running on.
    • Util_est (Utilization estimation).
    • Idle Cpu PELT (Per Entity Load-Tracking) update (Remote stats update).
    • Runtime scheduler domain flag detection.
    • Periodic load balance improvements.
    • Debugging tracepoints and procfs interfaces.

    Testing:

    • Boot testing on supported platforms.
    • Ran LISA's EAS tests (generic and load_tracking) on Arm Juno r2. Tests show 4/29 failures:

             > test_task_placement (tests.eas.generic.EnergyModelWakeMigration)

             > test_task_placement (tests.eas.generic.RampUp)

             > test_load_tracking (Test that the mean of the util_avg signal matched the expected value)

             > test_load_tracking (Test utilization propagation to cgroup root)

    Next work items:

    • Figuring out the reason why the tests fail.