Description of problem: High cpu usage of cppc_fie (1.5-2.5%) when idle Version-Release number of selected component (if applicable): Fedora Linux 35 (Server Edition Prerelease) How reproducible: CPU usage is constantly hovers between 1.5 and 2.5% - very reproducible. Steps to Reproduce: 1. Install Fedora 35 server edition on an aarch64 Ampere Altra machine. 2. Use top to view that CPU usage Actual results: CPU usage is between 1.5% and 2.5% when the machine is idle Expected results: CPU usage is less than 0.75 1.5% and 2.5% when the machine is idle
Then this isn't specific to my hacked up rpi4 with unmerged TFA/uefi patches to enable CPPC. This might be pretty significant if it is not an accounting problem. I saw this in 5.14 and instrumented the cppc call path to see if it was making excessive mailbox inquiries and it didn't appear to be the case.
Fix posted: https://lkml.org/lkml/2022/7/26/679 (although thinking about it I probably should have hidden the module parm or at least flipped its value if FIE is disabled)
This is fixed closing.