EFFICIENT BUFFER MANAGEMENT IN A MULTI-THREADED NETWORK INTERFACE

• US 20100332698A1
• Filed: 06/29/2009
• Published: 12/30/2010
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Muller, Shimon
• Granted Patent: US 7,970,963 B2
• Time in Patent Office: Days
• US Class Current: 710/57
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 49/9047 including multiple buffers, e.g. buffer pools

Abstract

Some embodiments of the present invention provide a system for receiving packets on a multi-threaded computing device which uses a memory-buffer-usage scorecard (MBUS) to enable multiple hardware threads to share a common pool of memory buffers. During operation, the system can identify a memory-descriptor location for posting a memory descriptor for a memory buffer. Next, the system can post the memory descriptor for the memory buffer at the memory-descriptor location. The system can then update the MBUS to indicate that the memory buffer is in use. Next, the system can store a packet in the memory buffer, and post a completion descriptor in a completion-descriptor location to indicate that the packet is ready to be processed. If the completion-descriptor indicates that the memory buffer is ready to be reclaimed, the system can reclaim the memory buffer, and update the MBUS to indicate that the memory buffer has been reclaimed.

Claims

1. A method for receiving a packet on a multi-threaded computing device which uses a memory-buffer-usage scorecard to enable multiple hardware threads to share a common pool of memory buffers, the method comprising:

identifying a memory-descriptor location for posting a memory descriptor for a memory buffer;

posting the memory descriptor for the memory buffer at the memory-descriptor location; and

updating the memory-buffer-usage scorecard to indicate that the memory buffer is in use.

2. The method of claim 1, wherein the memory descriptor includes a memory buffer address field.

3. The method of claim 1, wherein the memory descriptor includes a buffer index field which specifies an offset into a buffer address lookup table.

4. The method of claim 1, wherein the memory-descriptor location is a receive buffer ring (RBR) entry, and wherein the memory-buffer-usage scorecard is a buffer-posting and reclaim array (BPRA) which is partitioned into multiple regions so that a BPRA entry in each BPRA region is associated with an RBR entry.

5. The method of claim 4, wherein the memory descriptor includes a BPRA region field.

6. The method of claim 4, wherein updating the memory-buffer-usage scorecard to indicate that the memory buffer is in use comprises:

identifying a first BPRA entry in a first BPRA region which is associated with the RBR entry where the memory descriptor for the memory buffer is desired to be posted;

in response to determining that the first BPRA entry indicates that a memory buffer associated with the first BPRA entry has not been reclaimed, identifying a second BPRA entry in a second BPRA region which is associated with the first RBR entry, wherein the second BPRA entry indicates that a memory buffer associated with the second BPRA entry has been reclaimed; and

modifying the second BPRA entry to indicate that a memory buffer associated with the second BPRA entry has not been reclaimed.

7. The method of claim 6, wherein in response to determining that the first BPRA entry indicates that a memory buffer associated with the first BPRA entry has not been reclaimed, the method further comprises storing an indicator which indicates the first BPRA entry'"'"'s location in the first BPRA region.

8. The method of claim 7, wherein the indicator is used to determine which BPRA region to use when a BPRA entry in a current BPRA region is unavailable.

9. The method of claim 1, further comprising:

storing a packet in the memory buffer; and

posting a completion descriptor in a completion-descriptor location to indicate that the packet is ready to be processed.

10. The method of claim 9, further comprising:

in response to determining that the completion descriptor indicates that the memory buffer is ready to be reclaimed,

reclaiming the memory buffer, and

updating the memory-buffer-usage scorecard to indicate that the memory buffer has been reclaimed.

11. The method of claim 9, wherein the completion-descriptor location is a receive completion ring (RCR) entry.

12. The method of claim 9, wherein the completion descriptor includes a memory-buffer-type field which indicates the size of the packets that are stored in the memory buffer.

13. The method of claim 9, wherein the completion descriptor includes a packet offset field which indicates the packet'"'"'s location in the first memory buffer.

14. The method of claim 9, wherein the completion descriptor includes a packet length field which indicates the packet'"'"'s length.

15. The method of claim 9, wherein the completion descriptor includes a packet status field which indicates the packet'"'"'s status.

16. The method of claim 9, wherein the completion descriptor includes a buffer index field which specifies an offset into a buffer address lookup table.

17. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for receiving a packet on a multi-threaded computing device which uses a memory-buffer-usage scorecard to enable multiple hardware threads to share a common pool of memory buffers, the method comprising:

identifying a memory-descriptor location for posting a memory descriptor for a memory buffer;

posting the memory descriptor for the memory buffer at the memory-descriptor location; and

updating the memory-buffer-usage scorecard to indicate that the memory buffer is in use.

18. The computer-readable storage medium of claim 17, wherein the method further comprises:

storing a packet in the memory buffer;

posting a completion descriptor in a completion-descriptor location to indicate that the packet is ready to be processed;

in response to determining that the completion descriptor indicates that the memory buffer is ready to be reclaimed,

reclaiming the memory buffer, and

updating the memory-buffer-usage scorecard to indicate that the memory buffer has been reclaimed.

19. An apparatus for receiving a packet on a multi-threaded computing device which uses a memory-buffer-usage scorecard to enable multiple hardware threads to share a common pool of memory buffers, the apparatus comprising:

a memory; and

a buffer posting mechanism configured to;

identify a memory-descriptor location for posting a memory descriptor for a memory buffer;

post the memory descriptor for the memory buffer at the memory-descriptor location; and

update the memory-buffer-usage scorecard to indicate that the memory buffer is in use.

20. The apparatus of claim 19, further comprising:

a packet processing and buffer reclaiming mechanism to;

store a packet in the memory buffer;

post a completion descriptor in a completion-descriptor location to indicate that the packet is ready to be processed; and

in response to determining that the completion descriptor indicates that the memory buffer is ready to be reclaimed,

reclaim the memory buffer, and

update the memory-buffer-usage scorecard to indicate that the memory buffer has been reclaimed.