SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
The Sum of Blocks Per Port rule is an aggressive global control that sets and clears PFC triggers on receive ports due to conditions in any other port transmit FIFO regardless of receive traffic. When any transmit FIFO has a trigger condition set, all other receive ports will trigger PFC for that priority. This rule is intended to be configured in systems with high traffic rate jumbo packets on lower priorities.
A PFC priority is triggered by conditions in any other transmit FIFO by the below equation at any time:
priX_trig_set when the sum of all Tx FIFO blocks allocated on the port >= thresh_setX[4:0]
A PFC priority is cleared when conditions in all other Ethernet transmit FIFO’s satisfy the below equation at any time:
priX_trig_clr when the sum of all tx FIFO blocks allocated on the port <= thresh_clrX[4:0]
Where,