kata-containers/docs/design/core-scheduling.md

Core scheduling

Core scheduling is a Linux kernel feature that allows only trusted tasks to run concurrently on CPUs sharing compute resources (for example, hyper-threads on a core).

Containerd versions >= 1.6.4 leverage this to treat all of the processes associated with a given pod or container to be a single group of trusted tasks. To indicate this should be carried out, containerd sets the SCHED_CORE environment variable for each shim it spawns. When this is set, the Kata Containers shim implementation uses the prctl syscall to create a new core scheduling domain for the shim process itself as well as future VMM processes it will start.

For more details on the core scheduling feature, see the Linux documentation.