Apparatus and method for just-in-time transfer of transmit commands to a network interface

• US 7,046,628 B2
• Filed: 09/24/2001
• Issued: 05/16/2006
• Est. Priority Date: 09/24/2001
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Connor, Patrick L., Luhmann, Patrick J.
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): ROBERTS, BRIAN S
• Application Number:
  US09/963,077
• Publication Number:
  US 20030058852A1
• Time in Patent Office: 1,695 Days
• Field of Search: 370/230, 370/235, 370/389, 370/392, 370/412, 370/413, 370/463, 370/428, 370/429, 709/250, 709/231, 709/235, 710/35, 710 52- 57
• US Class Current: 370/230
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/56 implementing delay-aware scheduling
• 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 49/9063 Intermediate storage in different physical parts of a node or terminal

Abstract

A network driver provides additional transmit commands to a network interface when the number of transmit commands at the network interface falls below a specified threshold.

Claims

1. A method comprising:

assigning at least one descriptor to a packet;

providing the at least one descriptor to a network interface when an apparent descriptor total is less than a first threshold number of descriptors;

providing the at least one descriptor to a packet descriptor queue when the apparent descriptor total is greater than the first threshold; and

receiving an interrupt generated by the network interface, the interrupt indicating that an actual descriptor total is less than a second threshold number of descriptors.

2. The method of claim 1, further comprising:

providing a descriptor from the packet descriptor queue to the network interface in response to the interrupt.

3. The method of claim 1, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

4. The method of claim 1, further comprising recovering a processed descriptor from the network interface for reuse, the processed descriptor comprising a descriptor associated with a packet transmitted by the network interface.

5. A method comprising:

receiving at least one descriptor from a network driver when an apparent descriptor total is less than a first threshold number of descriptors, the at least one descriptor associated with a packet;

transmitting the packet to a network; and

asserting an interrupt when an actual descriptor total is less than a second threshold number of descriptors.

6. The method of claim 5, further comprising receiving a descriptor from a packet descriptor queue in response to assertion of the interrupt.

7. The method of claim 5, further comprising:

identifying a processed descriptor, the processed descriptor associated with a transmitted packet; and

providing the processed descriptor to the network driver for reuse.

8. The method of claim 5, further comprising:

fetching the packet from a memory, a location of the packet in the memory identified by the at least one descriptor; and

placing the packet in a packet FIFO.

9. The method of claim 5, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

10. A method comprising:

asserting an interrupt when an actual descriptor total is less than a second threshold number of descriptors;

receiving a descriptor from a packet descriptor queue in response to assertion of the interrupt; and

receiving another descriptor from a network driver when an apparent descriptor total is less than a first threshold number of descriptors.

11. The method of claim 10, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

12. The method of claim 10, further comprising:

identifying a processed descriptor, the processed descriptor associated with a transmitted packet; and

providing the processed descriptor to a network driver for reuse.

13. The method of claim 10, further comprising:

fetching a packet from a memory, a location of the packet in the memory identified by the descriptor; and

placing the packet in a packet FIFO.

14. A system comprising:

a processor coupled with a bus;

a memory coupled with the bus, the memory including a packet descriptor queue;

a network interface coupled with the bus and further coupled with a network;

a network driver resident in the memory, the network driver including a set of instructions that, when executed by the processor, cause the network driver to assign at least one descriptor to a packet;

provide the at least one descriptor to the network interface when an apparent descriptor total is less than a first threshold number of descriptors;

provide the at least one descriptor to the packet descriptor queue when the apparent descriptor total is greater than the first threshold; and

receive an interrupt from the network interface, the interrupt indicating that an actual descriptor total is less than a second threshold number of descriptors.

15. The system of claim 14, the network driver further including instructions that, when executed by the processor, cause the network driver to provide a descriptor from the packet descriptor queue to the network interface in response to the interrupt.

16. The system of claim 14, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

17. The system of claim 14, the network driver further including instructions that, when executed by the processor, cause the network driver to recover a processed descriptor from the network interface for reuse, the processed descriptor comprising a descriptor associated with a packet transmitted by the network interface.

18. A system comprising:

a processor coupled with a bus;

a memory coupled with the bus, the memory including a packet descriptor queue and a network driver resident thereon;

a network interface coupled with the bus and further coupled with a network, the network interface to

receive at least one descriptor from the network driver when an apparent descriptor total is less than a first threshold number of descriptors, the at least one descriptor associated with a packet;

transmit the packet to the network; and

assert an interrupt when an actual descriptor total is less than a second threshold number of descriptors.

19. The system of claim 18, the network interface to receive a descriptor from a packet descriptor queue in response to assertion of the interrupt.

20. The system of claim 18, the network interface to identify a processed descriptor, the processed descriptor associated with a transmitted packet;

and

provide the processed descriptor to the network driver for reuse.

21. The system of claim 18, the network interface to fetch the packet from the memory, a location of the packet in the memory identified by the at least one descriptor;

and

place the packet in the packet FIFO.

22. The system of claim 18, the second threshold number of packets equivalent to the first threshold number of packets.

23. An article of manufacture comprising:

a machine accessible medium providing content that, when accessed by a machine, causes the machine to

assign at least one descriptor to a packet;

provide the at least one descriptor to a network interface when an apparent descriptor total is less than a first threshold number of descriptors;

provide the at least one descriptor to a packet descriptor queue when the apparent descriptor total is greater than the first threshold; and

receive an interrupt generated by the network interface, the interrupt indicating that an actual descriptor total is less than a second threshold number of descriptors.

24. The article of manufacture of claim 23, wherein the content, when accessed, further causes the machine to:

provide a descriptor from the packet descriptor queue to the network interface in response to the interrupt.

25. The article of manufacture of claim 23, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

26. The article of manufacture of claim 23, wherein the content, when accessed, further causes the machine to recover a processed descriptor from the network interface for reuse, the processed descriptor comprising a descriptor associated with a packet transmitted by the network interface.

27. An article of manufacture comprising:

a machine accessible medium providing content that, when accessed by a machine, causes the machine to

receive at least one descriptor from a network driver when an apparent descriptor total is less than a first threshold number of descriptors, the at least one descriptor associated with a packet;

transmit the packet to a network; and

assert an interrupt when an actual descriptor total is less than a second threshold number of descriptors.

28. The article of manufacture of claim 27, wherein the content, when accessed, further causes the machine to receive a descriptor from a packet descriptor queue in response to assertion of the interrupt.

29. The article of manufacture of claim 27, wherein the content, when accessed, further causes the machine to:

identify a processed descriptor, the processed descriptor associated with a transmitted packet; and

provide the processed descriptor to the network driver for reuse.

30. The article of manufacture of claim 27, wherein the content, when accessed, further causes the machine to:

fetch the packet from a memory, a location of the packet in the memory identified by the at least one descriptor; and

place the packet in a packet FIFO.

31. The article of manufacture of claim 27, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

32. An article of manufacture comprising:

a machine accessible medium providing content that, when accessed by a machine, causes the machine to

assert an interrupt when an actual descriptor total is less than a second threshold number of descriptors;

receive a descriptor from a packet descriptor queue in response to assertion of the rnterrupt; and

receive another descriptor from a network driver when an apparent descriptor total is less than a first threshold number of descriptors.

33. The article of manufacture of claim 32, the second threshold number of descriptors equivalent to the first threshold number of descriptors.

34. The article of manufacture of claim 32, wherein the content, when accessed, further causes the machine to:

identify a processed descriptor, the processed descriptor associated with a transmitted packet; and

provide the processed descriptor to a network driver for reuse.

35. The article of manufacture of claim 32, wherein the content, when accessed, further causes the machine to:

fetch a packet from a memory, a location of the packet in the memory identified by the descriptor; and

place the packet in a packet FIFO.