Method and apparatus for accessing a memory

• US 7,617,376 B2
• Filed: 08/14/2003
• Issued: 11/10/2009
• Est. Priority Date: 08/14/2003
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Wendt, James G., Culley, Paul R., Hilland, Jeffrey R., Barron, Dwight L., Chadalapaka, Mallikarjun
• Primary Examiner(s): Kim; Matt
• Assistant Examiner(s): Dare; Ryan
• Application Number:
  US10/641,127
• Publication Number:
  US 20050038941A1
• Time in Patent Office: 2,280 Days
• Field of Search: 711/206
• US Class Current: 711/206
• CPC Class Codes: G06F 12/1081 for peripheral access to main memory, e.g. direct memory access [DMA]
• CPC Class Codes: G06F 13/4009 with data restructuring
• CPC Class Codes: H04L 67/00 Network arrangements or protocols for supporting network services or applications user-to-user messaging H04L51/00; network arrangements, protocols or services for supporting real-time applications in data packet communications networks H04L65/00

Abstract

The disclosed embodiments relate to an optimized memory registration mechanism that may comprise an upper layer protocol that associates I/O buffers with memory regions and that manages steering tags. The memory regions may be associated with a translation page table. The upper layer protocol may allocate one of the steering tags associated with at least one of the memory regions for a memory operation.

Claims

1. A memory access mechanism for a node, comprising:

an upper layer protocol;

a translation page table for storing data corresponding to a plurality of memory regions in the node; and

a plurality of steering tags that are controlled by the upper layer protocol, wherein the plurality of steering tags and resources to support the steering tags are allocated to the upper layer protocol that is part of the node prior to a latency sensitive operation, the upper layer protocol assigning at least one of the plurality of steering tags to be associated with at least one of the plurality of memory regions for a memory operation, wherein the assigning is performed in direct response to a request by a consumer.

2. The memory access mechanism set forth in claim 1, wherein the steering tags are allocated by execution of a verb.

3. The memory access mechanism set forth in claim 2, wherein the verb is executed at initialization.

4. The memory access mechanism set forth in claim 2, wherein the verb is executed after initialization.

5. The memory access mechanism set forth in claim 1, wherein the at least one of the plurality of steering tags is associated with an entry in the translation page table that is associated with the at least one of the plurality of memory regions.

6. The memory access mechanism set forth in claim 5, wherein the entry of the translation page table accesses a physical address table to access the at least one of the plurality of memory regions for the memory operation.

7. The memory access mechanism set forth in claim 1, wherein the translation page table uses a tagged offset in a request generated by the upper layer protocol to access the at least one of the plurality of memory regions for the memory operation.

8. The memory access mechanism set forth in claim 1, wherein the upper protocol layer is to further:

after allocation of the last one steering tag, receive a command for a memory access operation that involves the at least one memory region;

in response to the request, determine whether or not to use the allocated at least one steering tag; and

in response to determining that the allocated at least one steering tag is not to be used, acquire the allocated at least one steering tag and submit a request to input information into an entry of the translation page table associated with the allocated at least one steering tag.

9. The memory access mechanism set forth in claim 8, wherein the upper protocol layer is to further:

in response to determining that the allocated at least one steering tag is not to be used, issue a command for a memory registration to allocate a steering tag and associate such steering tag allocated in response to the command for the memory registration with an entry of the translation page table.

10. A first computer system for communication with a second computer system, comprising:

a consumer and at least one input/output device;

wherein the at least one input/output device comprises a memory access mechanism, the memory access mechanism comprising;

a plurality of buffers associated with the consumer; and

a plurality of steering tags that are managed by the consumer,

wherein the consumer is to issue a request to cause allocation of one of the plurality of steering tags to be associated with at least one of the plurality of buffers for a memory access operation, wherein the request is issued to cause allocation of the one steering tag prior to start of the memory access operation that is latency sensitive.

11. The first computer system set forth in claim 10, configured to generate a request for the memory access operation to be transmitted to the second computer system, wherein the request comprises the one of the plurality of steering tags.

12. The first computer system set forth in claim 10, wherein the memory access mechanism is to:

after allocation of the one steering tag, receive a command for a memory access operation that involves the at least one buffer;

in response to the request, determine whether or not to use the allocated one steering tag;

in response to determining that the allocated one steering tag is to be used, acquire the allocated one steering tag and submit a request to input information into an entry of an address translation table associated with the allocated one steering tag.

13. The first computer system set forth in claim 12, wherein the memory access mechanism is to further:

in response to determining that the allocated one steering tag is not to be used, issue a command for a memory registration to allocate a steering tag and associate such steering allocated in response to the command for the memory registration tag with an entry of the address translation table.

14. A method for providing access to a memory, the method comprising the acts of:

allocating, by a mechanism in a first node, a plurality of steering tags to an upper layer protocol in the first node, wherein allocating the plurality of steering tags occurs prior to a latency sensitive operation;

allocating a plurality of buffers associated with the upper layer protocol, wherein the plurality of buffers are part of the first node;

issuing command to a remote direct memory access network interface card in the first node after the allocation of the plurality of steering tags has been completed;

associating one of the steering tags to at least one of the plurality of buffers once a command is received at the upper layer protocol which associates buffer information that describes the at least one of the plurality of buffers associated with the one of the plurality of steering tags; and

advertising the one of the plurality of steering tags without waiting for the association to return a value.

15. The method set forth in claim 14, comprising communicating the one of the plurality of steering tags to a second node.

16. The method set forth in claim 14, comprising performing the command to access at least one of the plurality of buffers once the command is received at the remote direct memory access network interface card.

17. The method set forth in claim 14, wherein the allocation of the plurality of steering tags occurs at an initialization of the first node.

18. The method set forth in claim 14, comprising issuing a verb to perform the allocation of the plurality of steering tags.

19. The method set forth in claim 14, further comprising:

after allocation of the one steering tag, receiving a command for a memory access operation that involves the at least one buffer associated with the one steering tag;

in response to the request, determining whether or not to use the allocated one steering tag; and

in response to determining that the allocated one steering tag is to be used, acquiring the allocated one steering tag and submitting a request to input information into an entry of a translation page table associated with the allocated one steering tag.

20. The method set forth in claim 19, further comprising:

in response to determining that the allocated one steering tag is not to be used, issuing a command for a memory registration to allocate a steering tag and associate such steering tag allocated in response to the command for the memory registration with an entry of the translation page table.