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

@@ -137,9 +137,9 @@ The TWB scheduler (`zephyr_twb_schedule.c`) provides execution budget limits for
 ### Architecture
 
 -   **Separate Threads**: Similar to DP, each TWB task executes in its own Zephyr thread.
--   **Time Slicing**: When scheduled, the thread's granted cycle budget is translated to OS ticks (`k_thread_time_slice_set()`).
--   **Budget Exhaustion**: If the thread consumes its budget before completing its work for the tick, a callback (`scheduler_twb_task_cb()`) is invoked by the Zephyr kernel. This callback immediately drops the thread's priority to a background level (`CONFIG_TWB_THREAD_LOW_PRIORITY`), preventing starvation of other threads.
--   **Replenishment**: On the next LL tick (`scheduler_twb_ll_tick()`), the consumed cycles are reset, and the thread's original priority and time slice are restored, granting it a fresh budget.
+-   **Time Slicing**: When scheduled, the thread's execution budget is configured in OS ticks via `k_thread_time_slice_set()`. This tick-based budget is internally converted to hardware cycles for accounting against the CPU cycles actually consumed.
+-   **Budget Exhaustion**: If the thread consumes its budget (as measured in hardware cycles derived from the tick budget) before completing its work for the tick, a callback (`scheduler_twb_task_cb()`) is invoked by the Zephyr kernel. This callback immediately drops the thread's priority to a background level (`CONFIG_TWB_THREAD_LOW_PRIORITY`), preventing starvation of other threads.
+-   **Replenishment**: On the next LL tick (`scheduler_twb_ll_tick()`), the consumed hardware cycles are reset, and the thread's original priority and time slice are restored, granting it a fresh tick-based budget.
 
 ### Task State Diagram