Cpu clockspeed degraded when "isolcpus" and "nohz_full" are used on same CPUs with "intel_pstate" cpufreq driver.

Solution In Progress - Updated -

Issue

  • Cpu clockspeed degraded when 'isolcpus' and 'nohz_full' are used on same CPUs with 'intel_pstate' cpufreq driver. An example in following snippet.
# grep mhz -i /proc/cpuinfo 
cpu MHz     : 2299.694
cpu MHz     : 1200.988    ---->>>>>
cpu MHz     : 2300.335
cpu MHz     : 1201.245    ---->>>>>
cpu MHz     : 2299.951
cpu MHz     : 1281.353    ---->>>>>
cpu MHz     : 2299.438
cpu MHz     : 2302.642

Environment

  • Red Hat Enterprise Linux 7.

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