Created attachment 156271 [details] script that reproduces the problem (and doesn't thrash the cache) SUMMARY IO wait time is counted as CPU busy time by whichever underlying library is used plasma-systemmonitor, ksysguard, and desktop sensor widgets. STEPS TO REPRODUCE 1. Open the "history" view of plasma-systemmonitor, or the "System Load" tab of ksysguard, or have a system monitor widget using the "Core # Total Usage" sensor on your panel. 2. Run the attached script. If you don't have any SATA drives, change "/dev/sda" to something you do have. OBSERVED RESULT CPU usage appears to be 100%, even though the workload is totally I/O bound. EXPECTED RESULT CPU usage includes only % of time the CPU is executing instructions, matching the much lower value reported by htop. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora Linux 37 (available in About System) KDE Plasma Version: 5.26.5 KDE Frameworks Version: 5.102.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION This has probably been reported before, as bug 339164 against the plasma4 widget.
Created attachment 156272 [details] screenshot showing all 3 affected applications
Looks like I missed a few dupes. Guess I'm the first to report this against plasma-systemmonitor, though =P