Transmitting peer-to-peer transactions through a coherent interface

• US 20050251611A1
• Filed: 04/27/2004
• Published: 11/10/2005
• Est. Priority Date: 04/27/2004
• Status: Active Grant

• Current Assignee: Tahoe Research Limited (f/k/a Learndale Limited) (Vector Capital Corporation)
• Original Assignee: Intel Corporation
• Inventors: Ajanovic, Jasmin, Muthrasanallur, Sridhar, Blankenship, Robert G., Creta, Kenneth C.
• Granted Patent: US 7,210,000 B2
• Time in Patent Office: Days
• US Class Current: 710/316
• CPC Class Codes: G06F 13/387 for adaptation of different data processing systems to different peripheral devices, e.g. protocol converters for incompatible systems, open system
• CPC Class Codes: G06F 13/4265 on a point to point bus G06F13/4247, G06F13/4282 take precedence

Abstract

In various embodiments, the present invention includes a method for receiving a transaction having first header information from a first peer device at a first agent of a coherent system, inserting second header information onto the transaction, and routing the transaction to a second peer device using the second header information. In one such embodiment, the first header may be a header of a first protocol and the second header may be of a different protocol that is used to tunnel the transaction through the coherent system.

Claims

1. A method comprising:

receiving a transaction from a first peer device at a first agent of a coherent system, the transaction having first header information;

inserting second header information onto the transaction; and

routing the transaction to a second peer device using the second header information.

2. The method of claim 1, wherein inserting the second header information onto the transaction comprises tunneling the transaction from the first peer device to the second peer device through the coherent system.

3. The method of claim 1, further comprising retaining the first header information when transferring the transaction from the first agent to a second agent of the coherent system.

4. The method of claim 3, further comprising routing the transaction from the first agent to the second agent through at least one intermediate coherent device without translating the first header information.

5. The method of claim 1, wherein the first peer device comprises an input/output device coupled to the first agent via a non-coherent link.

6. The method of claim 1, wherein the second header information comprises a system interconnect header including a destination node identifier to identify a target agent of the coherent system.

7. The method of claim 2, further comprising preserving an end-to-end redundancy check when tunneling the transaction.

8. A method comprising:

tunneling a transaction from a first peer device to a second peer device through a common system fabric, wherein information associated with the transaction is preserved through the common system fabric.

9. The method of claim 8, wherein the transaction comprises a write transaction, and a first agent of the common system fabric splits the transaction into a plurality of write packets each having a system interconnect header, the information, and a portion of data of the transaction.

10. The method of claim 9, further comprising combining the plurality of write packets in a second agent of the common system fabric and transmitting the write transaction to the second peer device.

11. The method of claim 10, further comprising sending a completion packet from the second agent to the first agent after receipt of each of the plurality of write packets.

12. The method of claim 11, further comprising sending the completion packet on a different channel than the plurality of write packets.

13. The method of claim 9, wherein the portion of the data is less than a cacheline size of the common system fabric.

14. The method of claim 8, wherein the transaction comprises a read transaction, and a second agent of the common system fabric splits read data from the second peer device into a plurality of read packets each having a system interconnect header, the information, and a portion of the read data.

15. The method of claim 14, further comprising combining the plurality of read packets in a first agent of the common system fabric and transmitting the transaction to the first peer device.

16. The method of claim 15, further comprising sending a completion packet from the first agent to the second agent after receipt of each of the plurality of read packets.

17. An article comprising a machine-accessible storage medium containing instructions that if executed enable a system to:

tunnel a transaction from a first peer device to a second peer device through a common system fabric, wherein information associated with the transaction is preserved through the common system fabric.

18. The article of claim 17, further comprising instructions that if executed enable the system to split a write transaction into a plurality of write packets each having a system interconnect header, the information, and a portion of data of the transaction.

19. The article of claim 18, further comprising further comprising instructions that if executed enable the system to combine the plurality of write packets in an agent of the system and transmit the write transaction to the second peer device.

20. The article of claim 19, further comprising instructions that if executed enable the system to send a completion packet from the agent after receipt of each of the plurality of write packets.

21. A apparatus comprising:

a first agent to tunnel a transaction from a first peer device to a second peer device through a common system fabric, wherein information associated with the transaction is preserved through the common system fabric.

22. The apparatus of claim 21, further comprising a second agent coupled to the first agent, the second agent to receive the tunneled transaction.

23. The apparatus of claim 22, wherein the first agent and the second agent comprise input/output hubs.

24. The apparatus of claim 23, wherein the first peer device and the second peer device comprise input/output devices.

25. The apparatus of claim 24, wherein the information comprises a header of a non-coherent protocol.

26. A system comprising:

a first peer device; and

a first agent coupled to the first peer device to tunnel a transaction from the first peer device to a second peer device through a common system fabric, wherein information associated with the transaction is preserved through the common system fabric.

27. The system of claim 26, further comprising a second agent coupled to the first agent, the second agent to receive the tunneled transaction from the first agent.

28. The system of claim 27, wherein the first agent is adapted to insert header information onto the transaction, the header information usable to route the transaction to the second agent.

29. The system of claim 28, further comprising a third agent coupled between the first agent and the second agent, the third agent adapted to translate the header information.

30. The system of claim 27, wherein the first agent and the second agent comprise input/output hubs.