RTEMS Porting Guide
Should the body of the search loops in _Thread_queue_Enqueue_priority be unrolled one time? In unrolled each iteration of the loop examines two "nodes" on the chain being searched. Otherwise, only one node is examined per iteration.
If TRUE, then the loops are unrolled.
If FALSE, then the loops are not unrolled.
The primary factor in making this decision is the cost of disabling and enabling interrupts (_ISR_Flash) versus the cost of rest of the body of the loop. On some CPUs, the flash is more expensive than one iteration of the loop body. In this case, it might be desirable to unroll the loop. It is important to note that on some CPUs, this code is the longest interrupt disable period in RTEMS. So it is necessary to strike a balance when setting this parameter.
#define CPU_UNROLL_ENQUEUE_PRIORITY TRUE
RTEMS Porting Guide
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