ACE adds coherent transaction and snoop mechanisms to AXI; correct domains, ordering and software contracts are still required for agents to share cacheable memory.
ACE extends AXI with AC (snoop addr), CR (snoop resp), CD (snoop data) channels.
Shareability domains define which masters participate in coherency.
A coherent home/interconnect uses transaction type, domain and tracked state to determine which snoop or memory actions are required.
Survey branch after AXI handshakes. Read the cache-state lesson first if MESI is new; use the specialist Cache Coherency course for controller construction.
No. The dirty peer holds the newest 7, which the transaction must preserve while resolving permissions.
Follow a coherent read — Separate request, snoop response, data and completion.
Choose the participating domain — Check the region and device contract before adding maintenance.
Test a stale-data hypothesis — Collect the evidence that separates mapping, ordering and fabric faults.
Explain false sharing — Distinguish extra traffic from an incorrect value.