Method and apparatus for minimizing spinlocks and retaining packet order in systems utilizing multiple transmit queues

• US 20030058878A1
• Filed: 05/09/2002
• Published: 03/27/2003
• Est. Priority Date: 09/25/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Connor, Patrick L., Minnick, Linden
• Granted Patent: US 7,248,593 B2
• Time in Patent Office: Days
• US Class Current: 370/412
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 47/41 by acting on aggregated flows or links
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/6215 Individual queue per QOS, rate or priority

Abstract

A method, apparatus, and article of manufacture for retaining packet order in multiprocessor systems utilizing multiple transmit queues while minimizing spinlocks are disclosed herein. Embodiments of the present invention define multiple transmit queues for a given priority level of packets to allow parallel processing and queuing of packets having equal priority in different transmit queues. Queuing packets of equal priority in different transmit queues minimizes processor time spent attempting to acquire queue-specific resources associated with one particular transmit queue. In addition, embodiments of the present invention provide an assignment mechanism to maximize utilization of the multiple transmit queues by queuing packets corresponding to each transmit request in a next available transmit queue defined for a given priority level. Coordination between hardware and software allows the order of the queued packets to be maintained in the transmission process.

Claims

1. A method, comprising:

defining at least two transmit queues for a priority level group;

receiving at least two transmit requests substantially simultaneously, the at least two transmit requests corresponding to at least one packet, respectively, the at least one packet having a priority designation corresponding to the priority level group; and

processing the at least two transmit requests in parallel to queue the at least one packet corresponding to a first one of the at least two transmit requests in a first available one of the at least two transmit queues, and to queue the at least one packet corresponding to a second one of the at least two transmit requests in a next available one of the at least two transmit queues.

2. The method of claim 1, further comprising, indicating a queue location corresponding to a next packet to be transmitted.

3. The method of claim 1, wherein the priority level group corresponds to at least one communication protocol priority level.

4. The method of claim 1, wherein the priority level group comprises a single priority level.

5. The method of claim 1, wherein the priority level group comprises at least two priority levels.

6. The method of claim 2, wherein indicating a queue location includes setting an indicator associated with the at least one packet to identify one of the at least two transmit queues, the identified one of the at least two transmit queues corresponding to the next packet to be transmitted.

7. A method, comprising:

defining at least two transmit queues to correspond to at least one priority level;

receiving at least two transmit requests at a send packet function of a device driver substantially simultaneously, each of the at least two transmit requests corresponding to at least one packet, respectively;

assigning the at least one packet corresponding to each of the at least two transmit requests to a queue group in response to a priority designation, the queue group including the at least two transmit queues corresponding to the at least one priority level;

queuing the at least one packet corresponding to a first one of the at least two transmit requests in a first available one of the at least two transmit queues; and

queuing the at least one packet corresponding to a second one of the at least two transmit requests in a next available one of the at least two transmit queues.

8. The method of claim 7, wherein the priority designation corresponds to a communication protocol priority level.

9. The method of claim 7, wherein assigning the at least one packet corresponding to each of the at least two transmit requests to a queue group comprises correlating the priority designation with at least one priority level associated uniquely with the queue group.

10. The method of claim 7, further comprising, indicating a queue location corresponding to a next packet to be transmitted.

11. The method of claim 10, wherein indicating a queue location includes setting an indicator associated with the at least one packet corresponding to each of the at least two transmit requests to identify one of the at least two transmit queues, the identified one of the at least two transmit queues corresponding to the next packet to be transmitted.

12. An article of manufacture, comprising:

a machine-accessible medium including data that, if accessed by a machine, cause the machine to, define at least two transmit queues for a priority level group;

receive at least two transmit requests substantially simultaneously, the at least two transmit requests corresponding to at least one packet, respectively, the at least one packet having a priority designation corresponding to the priority level group; and

process the at least two transmit requests in parallel to queue the at least one packet corresponding to a first one of the at least two transmit requests in a first available one of the at least two transmit queues, and to queue the at least one packet corresponding to a second one of the at least two transmit requests in a next available one of the at least two transmit queues.

13. The article of manufacture of claim 12, further including data that, if accessed by the machine, cause the machine to indicate a queue location corresponding to a next packet to be transmitted.

14. The article of manufacture of claim 12, wherein the priority level group corresponds to at least one communication protocol priority level.

15. The article of manufacture of claim 12, wherein the priority level group comprises a single priority level.

16. The article of manufacture of claim 12, wherein the priority level group comprises at least two priority levels.

17. The article of manufacture of claim 13, wherein the data that, if accessed by the machine, cause the machine to indicate a queue location includes data that, if accessed by the machine, cause the machine to set an indicator associated with the at least one packet to identify one of the at least two transmit queues, the identified one of the at least two transmit queues corresponding to the next packet to be transmitted.

18. A article of manufacture, comprising:

a machine-accessible medium including data that, if accessed by a machine, cause the machine to,

define at least two transmit queues to correspond to at least one priority level;

receive at least two transmit requests at a send packet function of a device driver substantially simultaneously, each of the at least two transmit requests corresponding to at least one packet, respectively;

assign the at least one packet corresponding to each of the at least two transmit requests to a queue group in response to a priority designation, the queue group including the at least two transmit queues corresponding to the at least one priority level;

queue the at least one packet corresponding to a first one of the at least two transmit requests in a first available one of the at least two transmit queues; and

queue the at least one packet corresponding to a second one of the at least two transmit requests in a next available one of the at least two transmit queues.

19. The article of manufacture of claim 18, wherein the priority designation corresponds to a communication protocol priority level.

20. The article of manufacture of claim 18, wherein the data that, if accessed by the machine, cause the machine to assign the at least one packet corresponding to each of the at least two transmit requests to a queue group comprises data that, if accessed by the machine, cause the machine to correlate the priority designation with at least one priority level associated uniquely with the queue group.

21. The article of manufacture of claim 18, further including data that, if accessed by the machine, cause the machine to indicate a queue location corresponding to a next packet to be transmitted.

22. The article of manufacture of claim 21, wherein the data that, if accessed by the machine, cause the machine to indicate a queue location includes data that, if accessed by the machine, cause the machine to set an indicator associated with the at least one packet corresponding to each of the at least two transmit requests to identify one of the at least two transmit queues, the identified one of the at least two transmit queues corresponding to the next packet to be transmitted.

23. A system, comprising:

a plurality of processors to receive at least two transmit requests substantially simultaneously, each of the at least two transmit requests corresponding to at least one packet having a priority designation corresponding to a priority level group;

a communications interface, communicatively coupled to the plurality of processors, to transmit packets on a network; and

a memory, communicatively coupled to the plurality of processors, to store data and to provide at least two transmit queues accessible to the communications interface, the at least two transmit queues defined to correspond to the priority level group, and

in response to receipt of the at least two transmit requests substantially simultaneously at the plurality of processors, the plurality of processors process the at least two transmit requests in parallel to queue the at least one packet corresponding to a first one of the at least two transmit requests in a first available one of the at least two transmit queues and to queue the at least one packet corresponding to a second one of the at least two transmit requests in a next available one of the at least two transmit queues.

24. The system of claim 23, wherein the plurality of processors comprise a single processor with multiple threads.

25. The system of claim 23, wherein the priority level group corresponds to at least one communication protocol priority level.

26. The system of claim 23, wherein the plurality of processors indicate a queue location, corresponding to a next packet to be transmitted via the communications interface, in conjunction with each packet corresponding to each of the at least two transmit requests.

27. The system of claim 26, wherein the plurality of processors indicate the queue location by setting an indicator associated with the at least one packet to identify one of the at least two transmit queues, the identified one of the at least two transmit queues corresponding to the next packet to be transmitted via the communications interface.