Improving estimation of Task/CPU's utilization

This proposal has been rejected.


One Line Summary

Review of a possible alternative solution to the "decay-clamp" idea.


The “dynamic” nature of PELT makes it not completely generic to properly describe the utilization of all possible classes of tasks, and a prototype of the “decay clamping” solution, discussed at last year’s LPC, has been evaluated to be not suitable to properly fix these PELT’s behaviours.

Recently, a possible alternative solution has been posted on LKML 1 as a follow-up of an interesting discussion we had at the OSPM Summit [2,3].

Let’s review together if the idea to add a filter on top of PELT is a viable solution.



cpufreq, PELT, utilization-estimation


  • 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.