CXL and UALink Cross-Domain Translations with Caching for Reduced Latency Between CXL Fabrics and UALink Accelerator Interconnects

An apparatus comprising:

• a Compute Express Link (CXL) port configured to communicate with a first entity according to CXL;
• an Ultra Accelerator Link (UALink) port configured to communicate with a second entity according to an Ultra Accelerator Link Protocol Level Interface (UPLI);
• a cache;
• and
• a computer coupled to the CXL port, the UALink port, and the cache;
• wherein the computer is configured to:
• receive a CXL request from the first entity via the CXL port;
• perform a cache lookup based on the CXL request;
• responsive to a cache miss:
• translate the CXL request to a UPLI request, send the UPLI request to the second entity via the UALink port, receive a UPLI response comprising data from the second entity, store the data in the cache, translate the UPLI response to a CXL response, and send the CXL response comprising the data to the first entity via the CXL port;
• and
• responsive to a cache hit:
• send a CXL response comprising data from the cache to the first entity via the CXL port without sending to the second entity a UPLI request corresponding to the CXL request.

A method comprising:

• receiving, by a computer comprising a cache, an Ultra Accelerator Link Protocol Level Interface (UPLI) request comprising a read command from a first entity;
• performing, by the computer, a cache lookup based on the UPLI request;
• responsive to a cache miss:
• translating, by the computer, the UPLI request to a Compute Express Link (CXL) request;
• sending the CXL request to a second entity;
• receiving, from the second entity, a CXL response comprising data;
• storing the data in the cache;
• translating the CXL response to a UPLI read response;
• and
• sending the UPLI read response comprising the data to the first entity;
• and
• responsive to a cache hit:
• sending a UPLI read response comprising data from the cache to the first entity without sending to the second entity a CXL request corresponding to the UPLI request.

An apparatus comprising:

• an Ultra Accelerator Link (UALink) port configured to communicate with a first entity according to an Ultra Accelerator Link Protocol Level Interface (UPLI);
• a Compute Express Link (CXL) port configured to communicate with a second entity according to CXL;
• a cache;
• and
• a computer coupled to the UALink port, the CXL port, and the cache;
• wherein the computer is configured to:
• receive a UPLI request comprising a read command from the first entity via the UALink port;
• perform a cache lookup based on the UPLI request;
• responsive to a cache miss:
• translate the UPLI request to a CXL request, send the CXL request to the second entity via the CXL port, receive a CXL response comprising data from the second entity, store the data in the cache, translate the CXL response to a UPLI read response, and send the UPLI read response comprising the data to the first entity via the UALink port;
• and
• responsive to a cache hit:
• send a UPLI read response comprising data from the cache to the first entity via the UALink port without sending to the second entity a CXL request corresponding to the UPLI request.