High CPU utilization on RHEL 7 on HP ProLiant/Synergy with ondemand cpufreq governor and pcc-cpufreq driver
On RHEL 7.x high cpu usage (especially %sys) is observed while using ondemand governor (which is enabled by default) and pcc-cpufreq driver.
When system is booted, cpu utilization is high and it doesn't go down. Rebooting doesn't help since system "restores" to such behavior when useful workload is running on the system.
This issue is not cased by RCU-related kernel commit described here Higher CPU usage on RHEL7.3 using ondemand governor and pcc-cpufreq driver
- HP ProLiant DL360 Gen9 or HP Proliant DL380 Gen9 (or other HP DLxx series machines), HP Synergy 480 Gen9
- Different RHEL7 versions: from Red Hat Enterprise Linux 7.2 to Red Hat Enterprise Linux 7.5
- pcc-cpufreq driver is used
- ondemand cpufreq governor is enabled
- Seen on Gen7 hardware
- od_dbs_timer function seen in D state stacks
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