Communication error reporting mechanism in a multiprocessing computer system

• US 6,536,000 B1
• Filed: 10/15/1999
• Issued: 03/18/2003
• Est. Priority Date: 10/15/1999
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Hagersten, Erik E., Jackson, Christopher J.
• Primary Examiner(s): Beausoliel, Robert
• Assistant Examiner(s): Chu, Gabriel L.
• Application Number:
  US09/419,823
• Time in Patent Office: 1,250 Days
• Field of Search: 714/18, 714/44, 714/45, 714/48, 714/57, 714/25, 714/31, 714/43, 714/56
• US Class Current: 714/57
• CPC Class Codes: G06F 11/0724 in a multiprocessor or a multi-core unit multiprocessors per se G06F15/80
• CPC Class Codes: G06F 11/0772 Means for error signaling, e.g. using interrupts, exception flags, dedicated error registers

Abstract

A multiprocessing computer system includes a plurality of processing nodes, each having one or more processors, a memory, and a system interface. The plurality of processing nodes may be interconnected through a global interconnect network which supports cluster communications. The system interface of an initiating node may launch a request to a remote node'"'"'s memory or I/O. The computer system implements an error communication reporting mechanism wherein errors associated with remote transactions may be reported back to a particular processor which initiated the transaction. Each processor includes an error status register that is large enough to hold a transaction error code. The protocol associated with a local bus of each node (i.e., a bus interconnecting the processors of a node to the node'"'"'s system interface) includes acknowledgement messages for transactions when they have completed. In the event a transaction which is transmitted by a system interface upon the global interconnect network on behalf of a particular processor incurs an error, the system interface sets an error flag in the acknowledgement message and provides an associated error code. If the acknowledgement message denotes an error, the error code is written into the processor'"'"'s error status register for later retrieval by software. In various embodiments, a system interface may acknowledge a transaction to a given processor early (even if that transaction has not completed globally) if a subsequent transaction from the same processor is pending in the interface.

Claims

1. A subsystem for a multiprocessing computer system, said subsystem comprising:

a first processor coupled to a local bus, said first processor including a first error status register;

a second processor coupled to said local bus, said second processor including a second error status register;

a system interface coupled to said local bus, wherein said system interface is configured to receive transactions directed to one or more remote nodes which are initiated by said first and second processors, wherein said system interface is configured to provide a first error code to be stored within said first error status register in response to a first error being generated as a result of a first transaction initiated by said first processor, and wherein said system interface is configured to provide a second error code to be stored within said second error status register in response to a second error being generated as a result of a second transaction initiated by said second processor.

2. The subsystem as recited in claim 1 wherein said system interface is configured to provide said first error code to said first error status register via an acknowledgement message conveyed upon said local bus.

3. The subsystem as recited in claim 1 wherein said system interface includes a first request agent configured to convey a global transaction corresponding to said first transaction to a first remote node on behalf of said first processor, and wherein said system interface includes a second request agent configured to convey to said first remote node another global transaction corresponding to a subsequent transaction by said first processor.

4. The multiprocessing computer system as recited in claim 3, wherein said first request agent includes a first storage unit configured to store said first error code, and wherein said second request agent includes a second storage unit configured to store a third error code.

5. The multiprocessing computer system as recited in claim 4 wherein said first request agent is configured to provide an acknowledgement message to said first processor prior to said global transaction completing within said first remote node.

6. The multiprocessing computer system as recited in claim 5 wherein said second request agent is configured to convey a second acknowledgement message upon said local bus to said first processor in response to said subsequent transaction, wherein said second acknowledgement message includes said first error code.

7. The multiprocessing computer system as recited in claim 6 wherein said first processor includes an internal error status register, and wherein said first processor is configured to store said first error code within said internal error status register in response to said second acknowledgement message.

8. A multiprocessing computer system comprising a plurality of processing nodes and a global interconnect network interconnecting said plurality of processing nodes, wherein a first node includes:

a plurality of processors;

a memory coupled to said plurality of processors through a local bus; and

a system interface for receiving local transactions initiated by said plurality of processors on said local bus which are destined to remote nodes;

wherein each of said plurality of processors includes an error status register configured to store information regarding an error associated with a global transaction conveyed upon said global interconnect network by said system interface that corresponds to one of said local transactions;

wherein said system interface is configured to generate an acknowledgement message in response to a given transaction.

9. The multiprocessing computer system of claim 8, wherein said system interface is configured to convey said acknowledgement message to a given processor that initiated said given transaction through said local bus.

10. The multiprocessing computer system as recited in claim 9 wherein said given processor is configured to initiate said given transaction upon said local bus, and wherein said system interface includes a request agent configured to receive said given transaction and to convey said given transaction to a remote target node on behalf of said given processor.

11. The multiprocessing computer system of claim 10, wherein said request agent is configured to provide an error code with said acknowledgement message in response to receiving an error message from said remote target node.

12. The multiprocessing computer system of claim 11, wherein said error code is indicative of a time-out error conveyed by said remote target node.

13. The multiprocessing computer system of claim 11, wherein said error code is indicative of an access violation.

14. The multiprocessing computer system as recited in claim 10, wherein said request agent is configured to provide an error code with said acknowledgement message in response to detecting an error associated with said given transaction.

15. The multiprocessing computer system of claim 14, wherein said error code is indicative of a time-out error determined by said request agent.

16. The multiprocessing computer system as recited in claim 9, wherein said acknowledgement message is encodable to indicate an error.

17. The multiprocessing computer system as recited in claim 16, wherein said system interface includes a first request agent configured to convey said given transaction to a first remote node on behalf of said given processor, and wherein said system interface includes a second request agent configured to convey a second transaction to a second remote node on behalf of said given processor.

18. The multiprocessing computer system as recited in claim 17, wherein said first request agent includes a first storage unit configured to store a first error code, and wherein said second request agent includes a second storage unit configured to store a second error code.

19. The multiprocessing computer system as recited in claim 18 wherein said first request agent is configured to provide said acknowledgement message to said given processor prior to said given transaction completing within said first remote node.

20. The multiprocessing computer system as recited in claim 19 wherein said second request agent is configured to store a given error code generated in response to said given transaction, and wherein said second request agent is configured to convey a second acknowledgement message upon said local bus to said given processor in response to said second transaction, wherein said second acknowledgement message includes said given error code.

21. The multiprocessing computer system as recited in claim 20 wherein said given processor includes an internal error status register, and wherein said given processor is configured to store said given error code within said internal error status register in response to said second acknowledgement message.

22. A processor for use in a first node of a multiprocessing computer system that is interconnected with a plurality of additional processing nodes through a global interconnect network, wherein said first node includes a system interface for receiving transactions from said processor which are destined to at least one of said additional processing nodes, said processor comprising:

a processor core configured to initiate said transactions;

an error status register coupled to said processor core and configured to store error information regarding an error associated with a global transaction conveyed upon said global interconnect network by said system interface that correponds to a given transaction initiated by said processor core;

a bus interface configured to receive said error information from said system interface; and

software code executable to periodically poll said error status register to detect an error associated with said global transaction.

23. The processor of claim 22, wherein said error information is indicative of a time-out error associated with said global transaction.

24. The processor of claim 22, wherein said error information is indicative of an access violation indicated by one of said additional processing nodes.