Linux 4.9's CPUFreq To Make Greater Use Of Scheduler Info, IOWait Boosting

Written by Michael Larabel in Hardware on 3 October 2016 at 06:34 AM EDT. Add A Comment
The past few kernel releases there's been a redesign of CPUFreq and P-State code for being able to make use of the kernel's scheduler utilization data by these CPU frequency scaling drivers. That work also led to the introduction of the Schedutil governor. Work along this line has continued for Linux 4.9.

Rafael Wysocki sent in the ACPI and power management pull requests on Sunday night for the Linux 4.9 kernel. With the power management updates, the CPUFreq driver was changed to allow the scheduler to pass hints to the governors' utilization update callbacks. This latest work adds support for IOwait boosting to the Schedutil governor and the Intel P-Sstate driver for boosting the performance if the enqueued task was previously waiting on I/O.

The power management pull request also has some fixes around the Schedutil code, support for more ARM platforms in CPUFreq-DT, and a variety of other updates.

The ACPI update has ACPICA code updates, a new ACPI WDAT (Watchdog Action Table) driver, and other ACPI updates and fixes. Details on that here.
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