CPUFreq without timers and the schedutil governor

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Power Management and Energy-awareness
Microconference Session

One Line Summary

Summarize recent advances in CPUFreq development and discuss the next steps.

Abstract

In Linux 4.6 and 4.7 we have eliminated timers from CPUFreq by making the scheduler invoke CPUFreq governors via per-CPU callbacks and introduced a new CPUFreq governor, called schedutil, that is part of the scheduler and makes decisions based on PELT. Under development are enhancements of that code (update reason flags, IOwait boost, cross-CPU updates), so discuss them and explore future development directions.

Tags

kernel, cpu, scheduler, pm, cpufreq, schedutil

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Speaker

  • Rjw

    Rafael Wysocki

    Intel OTC

    Biography

    I am the maintainer of the Linux kernel’s core ACPI and power management code, including the core infrastructure for IO device PM, CPU PM and system suspend/hibernation. I work at Intel Open Source Technology Center as a Software Engineer with focus on the mainline Linux kernel. I’ve been actively contributing to Linux since 2005, in particular to the kernel’s suspend/hibernate subsystem, power management in general (IO runtime PM framework, cpufreq, cpuidle, PM QoS, wakeup framework etc.), hot-plug infrastructure, ACPI core and PCI core. Since 2008 I’ve given presentations at multiple Linux Foundation conferences and other Linux-related events, including the Linux Foundation Collaboration Summit, LinuxCon (North America/Japan/Europe), Linux Plumbers Conference, Linux.conf.au, LinuxTag, and Ottawa Linux Symposium. I hold a PhD (2002) in physics from the University of Warsaw, Poland.