1.5 CCI operation

The CCI-550 has dual-layer request channels, meaning that it can handle two requests per cycle. It also has a central Transaction Tracker (TT) that handles coherency and ordering. The TT is non-blocking and can reorder requests according to QoS requirements.

The following figure shows the CCI-550 high-level operation.
Figure 1-2 CCI-550 high-level operation
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The TT uses a snoop filter to determine where to send snoop requests. To maximize throughput:
  • The snoop filter has four partitions.
  • The read data and write data interconnects are fully-connected crossbars.
Write responses also use a crossbar interconnect and the reorder buffer helps the CCI-550 to meet ordering requirements without stalling requests.
Each interface has a configurable number of register stages, with a minimum of one stage for each interface.
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