Intel Developing New CPU Idle Governor For Tickless Systems

Written by Michael Larabel in Intel on 1 January 2019 at 08:40 AM EST. Add A Comment
Linux power management expert Rafael Wysocki, who is also the maintainer of the ACPI/PM subsystems, has been working on the "TEO" the past few months as the Timer Events Oriented governor for CPUIdle framework.

The CPUIdle governor is responsible for deciding the desired C-state of the CPU/system. Rafael has been working on this new "TEO" governor for Linux tickless systems with this new design that is smarter and potentially offers some minor performance benefits. Rafael explained, "the timer events oriented (TEO) governor, uses the same basic strategy as menu: it always tries to find the deepest idle state that can be used in the given conditions. However, it applies a different approach to that problem."

The code comments also go on to explain, "this governor estimates whether or not the upcoming idle time of the CPU is likely to be significantly shorter than the sleep length and selects an idle state for it in accordance with that." This governor is now up to its tenth revision but isn't ready in time for merging to the ongoing Linux 4.21 merge window.

Those wishing to test out the new CPUIdle TEO governor or to read more about it, the latest version of the patch can be found on linux-pm. Hopefully we'll see this in Linux 4.22 and of course plan on benchmarking it when the time comes.
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