7.Locks HexConnections

A "sched/fair" change for Linux 5.20 aims to enhance the efficiency when searching for an idle CPU under heavy system load. The change led by Intel should improve the kernel's efficiency when the system is overloaded but as with most low-level tuning does run the risk of regressions.

Intel's Chen Yu worked out this new "SIS_UTIL" scheduler feature to search for an idle CPU based on the sum of the utilization average. This stems from finding that the kernel's select_idle_cpu() is too time consuming when looking for an idle CPU while the system is overloaded.


The patch though did already yield a regression within the Stress-NG socket benchmark but is an area for further investigation. There was also a slight regression in at least one Hackbench test configuration.