RHEL 7 - What minimum kernel is required to support proper cpuscaling behavior on systems with certain Intel Xeon and Intel Core CPU's

Environment

• Component
  • cpuscaling
• Products
  • Red Hat Enterprise Linux 7 Update 2
  • Red Hat Enterprise Linux 7 Update 3
  • Red Hat Enterprise OpenStack Platform (RHELOSP) 5
  • Red Hat Enterprise OpenStack Platform (RHELOSP) 6
  • Red Hat Enterprise OpenStack Platform (RHELOSP) 7
  • Red Hat OpenStack Platform (RHOSP) 8
  • Red Hat OpenStack Platform (RHOSP) 9
  • Red Hat OpenStack Platform (RHOSP) 10
  • Red Hat OpenStack Platform (RHOSP) 11
• Servers, Workstations and Desktops with the following Intel CPU's
  • Intel Xeon® Processor E3 v6 Family
  • Intel Xeon® Processor E5 Family
  • Intel Xeon® Processor E5 v2 Family
  • Intel Xeon® Processor E5 v3 Family
  • Intel Xeon® Processor E5 v4 Family
  • Intel Xeon® Processor E7 v3 Family
  • Intel Xeon® Processor E7 v4 Family
  • Intel Xeon® Processor 81XX (Platinum) Family
  • 4th Generation Intel Core i7 Processors
  • 4th Generation Intel Core i5 Processors
  • Intel® Pentium® Processor D1500 Family (Server Series)

Issue

It was found that the intel_pstate driver had a calculation error that was resulting in incorrect rounding of the cpu frequency. The defect results in the CPU not being able to reach all available frequencies as the driver scales the CPU frequency up and down in response to system load.

Resolution

The table below notes the Minimum Errata Kernel Version required to support proper cpuscaling behavior on systems using the Intel CPU's listed in the environment section of this Knowledge Base Article. Systems using these CPU's now exhibit correct cpuscaling behavior when using the Minimum Errata Kernel Version. If this Knowledge Base Article is associated with a certified hardware entry in the Red Hat Certification Catalog (https://access.redhat.com/certifications) that hardware required the Minimum Errata Kernel Version or a Later Errata Kernel Version to pass certification.