Update src/schedule/README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Liam Girdwood <lgirdwood@gmail.com>

Author: lgirdwood

src/schedule/README.md

@@ -8,7 +8,7 @@ SOF categorizes tasks and assigns them to specialized schedulers:
 
 1.  **LL (Low Latency) Scheduler**: For tasks that require strict, predictable, and lowest possible latency bound to hardware events (Timers, DMA interrupts).
 2.  **DP (Data Processing) Scheduler**: For compute-intensive components that process large chunks of data and operate on deadlines rather than strict cycles.
-3.  **TWB (Thread With Budget) Scheduler**: For tasks that are allotted a specific execution "budget" (in CPU cycles) per tick to prevent CPU starvation.
+3.  **TWB (Thread With Budget) Scheduler**: For tasks that are allotted a specific execution "budget" per scheduler tick, expressed in Zephyr time-slice ticks (e.g. derived from `ZEPHYR_TWB_BUDGET_MAX` in OS ticks), which the runtime then uses to limit and account for CPU cycles to prevent starvation.
 
 Below is a high-level component interaction architecture of the SOF scheduling domains on top of Zephyr.