sched_ext

sched_ext lets you run alternative CPU schedulers on Linux. A CPU scheduler decides how processor time is shared between applications. Different schedulers can change how your system responds under load; a different scheduler is not automatically faster.

Keep the kernel’s default scheduler as your baseline. Compare alternatives with the same applications and workload, and keep the one that works better on your hardware.

How the tools fit together

• Scheduler binaries implement the scheduling behavior.
• scx.service starts the selected scheduler and supports starting it at boot.
• scxcli selects schedulers, manages their saved configuration and reports status.
• scxtui provides a terminal menu for the same switching workflow.

The upstream project develops sched_ext schedulers and tools. The Seafoam Labs fork provides Devario’s integration. Package contents vary by distribution: these guides cover the scxtui / scxcli / scx.service workflow. A scheduler that exits returns control to the kernel’s own scheduler.

Start here

InstallationChoose Devario or Arch-based instructions and check your kernel and tools.

Using schedulersSwitch schedulers, manage boot persistence and return to Default.

Configuration and profilesSet custom options, manage profiles and test service overrides.

TroubleshootingRead status, investigate failures and collect useful diagnostics.

Pearl desktop controls

Pearl also has graphical scheduler controls. Their profile files and helper requirements belong to Pearl’s scheduling documentation; they are not interchangeable with the scxcli catalog. Use that guide for the Pearl Settings interface and these guides for the terminal tools.

Developer references

This page adapts the sched_ext guide for Devario by sir_lucjan. It describes the scxtui / scxcli / scx.service workflow in the current source. Devario’s release package is built from v1.1.5-devario5.

• scxcli reference: commands, privileges and custom profiles.
• scxtui reference: requirements, keyboard controls and interface behavior.
• Catalog contract: schema, trust rules, status detection and client integration.
• Scheduler descriptions: individual schedulers and their intended workloads.
• Upstream installation: source builds and other distributions. A tools-only build does not install scheduler binaries.
• Seafoam Labs scx fork: Devario integration and scheduler development.
• Devario package recipes: package contents and build configuration.