Everything you need from an RTOS, nothing you don't. Bring your own HAL.
Mixed cooperative and preemptive scheduling, or KERNEL_HRT with kernel-monitored deadlines and miss callbacks.
Create tasks once at startup, or create and exit them at runtime.
Optional ThreadX-style per-task time quantum, adjustable at run time.
Periodic ticks for simplicity or timer-based wakeups to maximize sleep time.
One STK instance per physical core for lock-free performance.
Attach your own scheduling algorithm by implementing the C++ strategy interface.
Privileged and user tasks, up to 6 per-task regions reprogrammed on every context switch, hardware stack guard.
Secure-only scheduling in the open-source driver. Full Secure plus Non-Secure scheduling via the commercial interface.
MCAS (2-level) and MCAS4 (4-level) adaptive schedulers with automatic escalation and recovery.
Rich primitives in stk::sync.
BlockMemoryPool and BytePool allocators.
Per-task TLS via a dedicated CPU register.
FreeRTOS, CMSIS-RTOS2 and pthread wrappers.
SEGGER SystemView scheduling traces.
lwIP, mbedTLS, TinyUSB and Raspberry Pi Pico SDK.
| Strategy | Mode | License |
|---|---|---|
| Round-Robin, SWRR | Soft / HRT | MIT |
| Fixed-Priority (32 levels, priority inheritance) | Soft / HRT | MIT |
| Preemption-Threshold (PTS, optional time-slicing) | Soft | MIT |
| RM, DM, EDF (with WCRT analysis for RM/DM) | HRT | MIT |
| MCAS (2-level), MCAS4 (4-level) | HRT | Commercial |
SuperTinyKernel