About EDF SMP Behaviour

[Richi Dubey]

Hi,

Can someone please explain this behavior of EDF SMP Scheduler on a 4 CPU
system, with INIT task pinned to cpu 0:


Before Task 3 (Priority 6, Affined to CPU 3) arrival:

CPU 1 is executing: Task 1 (Priority 5, Affined to CPU 1)
CPU 2 is executing: Task 2 (Priority 7, Affined to CPU 2)
CPU 3 is executing: Task 0 (Priority 3, Affined to ALL)

After Task 3 arrival:
CPU 1 is executing: Task 1 (Priority 5, Affined to CPU 1)
CPU 2 is executing: Task 0 (Priority 3, Affined to ALL)
CPU 3 is executing: Task 3 (Priority 6, Affined to CPU 3)

How did Task 3 force Task 0 out of its CPU when Task 0 has a higher
priority? Is thread helping involved?
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