Utilization clamping support for the CPU controller

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One Line Summary

Discussion on the proposal for a per-task API to bias OPP selection.


A recently updated proposal has been posted on LKML 1 to support per-task boosting and capping of CPU frequencies.

As a follow up of the discussion we had at the OSPM Summit [2,3], it would be useful to review these main points:
- Is the concept of “utilization clamping” acceptable?
- Are the identified use-cases good enough to justify the new API?
- Is the CGroups interface ok or should we add also another “primary” interface?
- Is the reference-counting based implementation ok?

1 https://lkml.org/lkml/2017/8/24/721
2 http://retis.sssup.it/ospm-summit/Downloads/OSPM_SchedTune.pdf
3 https://youtu.be/6MC1jbYbQTo


scheduler, cgroups, android, cpufreq, API, power/performance


  • Pb_goldengate

    Patrick Bellasi

    ARM Ltd


    Patrick Bellasi is a Senior Software Engineer at ARM Ltd (Cambridge) working as a Linux scheduler specialist on Energy Aware Scheduling for ARM big.LITTLE technology.

    He developed the EAS ‘SchedTune’ extension to provide per-task energy-vs-performance tuning which has been merged into the Android Common Kernel. He is also responsible for configurable tooling (LISA, BART, TRAPpy) used to analyse scheduler behaviour in product applications.

    Previously, Patrick has been a Post-Doc at Politecnico di Milano, working in cooperation with STMicroelectronics in different projects related to SoCs energy optimization and run-time resource management of experimental many-core architectures.