µC/OS-III handles event posting from interrupts using two different methods: Direct and Deferred Post. These will be discussed in greater detail in Interrupt Management. From a scheduling point of view, the end result of the two methods is the same; the highest priority ready task will receive the CPU as shown in the figures below.
The figure below shows that µC/OS-III performs a few extra steps when it is configured for the Deferred Post method. Notice that the end results is the same; the high-priority task preempts the low-priority one.