SDCI can operate in the following modes:
- “No Steering Tag (No ST)” mode:
- If the cache line being written to by the Ethernet adapter is already in a cache, the write is delivered to that cache.
- If the cache line being written to by the Ethernet adapter is not present in a cache, the write goes to memory as normal.
This can work well for polling workloads where applications naturally cause the cache lines they are interested in to be in the relevant caches.
- “SDCI with steering tags” mode:
In this mode the Ethernet adapter specifies the core complex (CCX) to target for its writes. All writes on the receive queue for the stack are steered to an L2 cache associated with the specified core complex.