Crate scx_utils

source ·
Expand description

§Utility collection for sched_ext schedulers

sched_ext is a Linux kernel feature which enables implementing kernel thread schedulers in BPF and dynamically loading them.

Thie crate is a collection of utilities for sched_ext scheduler implementations which use Rust for userspace component. This enables implementing hot paths in BPF while offloading colder and more complex operations to userspace Rust code which can be significantly more convenient and powerful.

The utilities can be put into two broad categories.

§Build Utilities

BPF being its own CPU architecture and independent runtime environment, build environment and steps are already rather complex. The need to interface between two different languages - C and Rust - adds further complexities. This crate contains struct BpfBuilder which is to be used from build.rs and automates most of the process.

§Utilities for Rust Userspace Component

Utility modules which can be useful for userspace component of sched_ext schedulers.

Modules§

Macros§

  • paste
  • scx_ops_attach
    Must be used together with scx_ops_load!(). See there.
  • scx_ops_load
    struct sched_ext_ops can change over time. If compat.bpf.h::SCX_OPS_DEFINE() is used to define ops and scx_ops_load!() and scx_ops_attach!() are used to load and attach it, backward compatibility is automatically maintained where reasonable.
  • uei_exited
    Takes a reference to C struct user_exit_info and test whether the BPF scheduler has exited. See UserExitInfo.
  • uei_read
    Takes a reference to C struct user_exit_info and reads it into UserExitInfo. See UserExitInfo.
  • uei_report
    Takes a reference to C struct user_exit_info, reads it and invokes UserExitInfo::report() on it. See UserExitInfo.
  • uei_set_size
    Resize debug dump area according to ops.exit_dump_len. If this macro is not called, debug dump area is not allocated and debug dump won’t be printed out.
  • warn
    Logs a message at the warn level.

Structs§

Enums§

Statics§

Functions§