Linux 4.20 Scheduler To Better Deal With "Misfit" Tasks On ARM big.LITTLE Systems

The next Linux kernel has scheduler improvements that will benefit some tasks when running on ARM big.LITTLE type systems where select CPU cores are much more powerful than the other cores.

With the scheduler updates for the Linux 4.20~5.0 kernel, the kernel will now better migrate CPU-intense tasks on asymmetric CPU capacity systems. In particular, for most modern/high-end ARM SoCs with a "big.LITTLE" design where some of the ARM cores are much faster but consume more power and are complemented by lower-power cores like the ARM Cortex-A53.

The Linux scheduler will now better migrate "misfit" tasks to the much faster CPU cores if there is sufficient computing capacity available. More details on the heuristics are outlined via this patch comment. Related to this CPU task migration work to bigger cores are also topology handling improvements for dealing with CPU capacity changes. These patches made it into Linux 4.20~5.0 via this Git pull.