Arbitrating virtual channel transmit queues in a switched fabric network

• US 20060140126A1
• Filed: 12/27/2004
• Published: 06/29/2006
• Est. Priority Date: 12/27/2004
• Status: Abandoned Application

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Zhong, Tina C., Mitchell, James
• Application Number:
  US11/024,361
• Publication Number:
  US 20060140126A1
• Time in Patent Office: Days
• US Class Current: 370/241
• CPC Class Codes: H04L 47/50 Queue scheduling
• CPC Class Codes: H04L 47/6285 Provisions for avoiding starvation of low priority queues
• CPC Class Codes: H04L 49/35 Switches specially adapted for specific applications

Abstract

A device in an AS fabric may include an event dispatch unit for generating event packets to be sent over the fabric to event handling agents. The AS device may arbitrate between different packets for the resources of a particular VC. The AS device may arbitrate between packets from different VCs downstream in the AS transaction layer while giving preference to high priority packets.

Claims

1. An apparatus comprising:

an event arbiter to select an event from at least one reported event;

an event identifier to identify information relating to the event and determine whether to generate an event reporting packet; and

a packet generator to generate the event reporting packet corresponding to the event; and

a mapping module to map the event reporting packet to a virtual channel on which to send the packet.

2. The apparatus of claim 1, wherein the event arbiter is operative to receive events from one or more event reporting agents in an Advanced Switching device.

3. The apparatus of claim 2, wherein the event identifier is operative to access an entry corresponding to the event in an event table in a capability structure of the Advanced Switching device.

4. The apparatus of claim 1, wherein the event identifier is operative to identify the event based on a class and subclass of the event.

5. The apparatus of claim 1, wherein the event reporting packet comprises a protocol interface (PI)-5 packet.

6. The apparatus of claim 1, wherein the event identifier is operative to determine

whether to block the event,

whether to handle the event locally, or

whether to generate the event reporting packet for transmission on the switched fabric.

7. A method comprising:

receiving one or more events from one or more event reporting agents;

selecting one of the events;

identifying information relating to the event;

determining whether to generate an event reporting packet corresponding to the event;

generating the event reporting packet, the event reporting packet having a traffic class; and

mapping the traffic class of the event reporting packet to a virtual channel on which to send the packet.

8. The method of claim 7, wherein said receiving the one or more events comprises receiving one or more events from one or more event reporting agents in an Advanced Switching device.

9. The method of claim 8, wherein said identifying information relating to the event comprises accessing an entry corresponding to the event in an event table in a capability structure of the Advanced Switching device.

10. An article comprising a machine-readable medium including machine-executable instructions to cause a machine to:

receive one or more events from one or more event reporting agents;

select one of the events;

identify information relating to the event;

determine whether to generate an event reporting packet corresponding to the event;

generate the event reporting packet, the event reporting packet having a traffic class; and

map the traffic class of the event reporting packet to a virtual channel on which to send the packet.

11. The article of claim 10, wherein the instructions to cause the machine to receive the one or more events comprise instructions to cause the machine to receive one or more events from one or more event reporting agents in an Advanced Switching device.

12. The article of claim 11, wherein the instructions to cause the machine to identify information relating to the event comprise instructions to cause the machine to accessing an entry corresponding to the event in an event table in a capability structure of the Advanced Switching device.

13. A system comprising:

a switched fabric; and

a node coupled to the switched fabric, the node including;

an event arbiter to select an event from one or more reported events;

an event identifier to identify information relating to the event and determine whether to generate an event reporting packet;

a packet generator to generate the event reporting packet corresponding to the event, the event reporting packet having a traffic class; and

a mapping module to map the traffic class of the event reporting packet to a virtual channel on which to send the packet.

14. The system of claim 13, wherein the switched fabric comprises an Advanced Switching network.

15. An apparatus comprising:

a first queue corresponding to a virtual channel;

a second queue corresponding to the virtual channel;

a control unit to

select a packet from one or more available packets, and

determine if the packet is of a first type or a second type; and

a queue controller to

receive the packet from the control unit,

store the packet in the first queue if the packet is of the first type and the first queue is not full, and in response to the first queue being full, wait until the first queue is not full, and

store the packet in the second queue if the packet is of the second type and the second queue is not full, and in response to the second queue being full, wait for a packet of the first type.

16. The apparatus of claim 15, wherein the queue controller is operative to:

in response to the packet being of the second type and the second queue being full, receive a packet of the first type;

store the packet of the first type in the first queue if the first queue is not full, and in response to the first queue being full, wait until the first queue is not full; and

after storing the packet of the first type in the first queue, store the packet of the second type in the second queue if the second queue is not full, and in response to the second queue being full, wait for another packet of the first type.

17. The apparatus of claim 15, wherein the queue controller comprises a state machine including one or more states corresponding to packets of the first type and one or more states corresponding to packets of the second type.

18. The apparatus of claim 15, wherein the apparatus comprises an Advance Switching device.

19. The apparatus of claim 18, wherein the virtual channel comprises a bypass capable virtual channel,

wherein the first type of packet comprises an ordered-only packet, and

wherein the second type of packet comprises a bypass capable packet.

20. A method comprising:

selecting a packet from one or more available packets for a virtual channel;

determining if the packet is of a first type or a second type;

storing the packet in a first queue if the packet is of the first type and the first queue is not full, and in response to the first queue being full, waiting until the first queue is not full; and

storing the packet in a second queue if the packet is of the second type and the second queue is not full, and in response to the second queue being full, waiting for a packet of the first type.

21. The method of claim 20, wherein said storing the packet in the second queue further comprises:

receiving the packet of the first type;

storing the packet of the first type in the first queue if the first queue is not full, and in response to the first queue being full, waiting until the first queue is not full; and

after storing the packet of the first type in the first queue, storing the packet of the second type in the second queue if the second queue is not full, and in response to the second queue being full, waiting for another packet of the first type.

22. The method of claim 20, wherein said selecting a packet comprises selecting a packet for a bypass capable virtual channel in an Advance Switching network.

23. The method of claim 20, wherein said determining comprises determining whether the packet is an ordered-only packet or a bypass capable packet.

24. An article comprising a machine-medium including machine-executable instructions to cause a machine to:

select a packet from one or more available packets for a virtual channel;

determine if the packet is of a first type or a second type;

store the packet in a first queue if the packet is of the first type and the first queue is not full, and in response to the first queue being full, waiting until the first queue is not full; and

store the packet in a second queue if the packet is of the second type and the second queue is not full, and in response to the second queue being full, waiting for a packet of the first type.

25. The article of claim 24, wherein the virtual channel comprises a bypass capable virtual channel in an Advance Switching network.

26. A system comprising:

a switched fabric; and

a node coupled to the switched fabric, the node including;

a first queue corresponding to a virtual channel;

a second queue corresponding to the virtual channel;

a control unit to

select a packet from one or more available packets, and

determine if the packet is of a first type or a second type; and

a queue controller to

receive the packet from the control unit,

store the packet in the first queue if the packet is of the first type and the first queue is not full, and in response to the first queue being full, wait until the first queue is not full, and

store the packet in the second queue if the packet is of the second type and the second queue is not full, and in response to the second queue being full, wait for a packet of the first type.

27. The system of claim 26, wherein the virtual channel comprises a bypass capable virtual channel in an Advanced Switching system,

wherein the first type of packet comprises an ordered-only packet, and

wherein the second type of packet comprises a bypass capable packet.

28. An apparatus comprising:

an interface to receive a plurality of packets from a plurality of packet queues, each packet queue corresponding to one virtual channel; and

a packet arbiter to determine if the plurality of packets include one or more high priority packets, and to select from the high priority packets until said high priority packets are exhausted.

29. The apparatus of claim 28, wherein the plurality of packet queues comprise one or more dedicated high priority packet queues including only high priority packets.

30. The apparatus of claim 29, wherein the arbiter is operative to

determine if the plurality of packet queues include a plurality of high priority packet queues, and

select from the plurality of high priority packet queues using a round robin scheme until the high priority packets are exhausted.

31. The apparatus of claim 28, wherein the interface comprises a multiplexer and the packet arbiter includes a state machine including a state for each packet queue.

32. The apparatus of claim 28, wherein the apparatus comprises an Advanced Switching device.

33. The apparatus of claim 32, wherein the high priority packets comprise TC7 packets.

34. A method comprising:

receiving a plurality of packets from a plurality of packet queues, each packet queue corresponding to one virtual channel;

determining if the plurality of packets include one or more high priority packets; and

selecting from the high priority packets until said high priority packets are exhausted.

35. The method of claim 34, further comprising:

determining if the plurality of packet queues include a plurality of high priority packet queues; and

in response to the plurality of packet queues including a plurality of high priority packet queues, selecting from the plurality of high priority packet queues using a round robin scheme until the high priority packets are exhausted.

36. The method of claim 34, wherein said receiving the plurality of packets comprises receiving a plurality of packets from a plurality of packet queues in an Advanced Switching device.

37. The method of claim 36, wherein said determining comprises determining if the plurality of packets include one or more TC7 packets.

38. An article comprising a machine-readable medium including machine-executable instructions to cause a machine to:

receive a plurality of packets from a plurality of packet queues, each packet queue corresponding to one virtual channel;

determine if the plurality of packets include one or more high priority packets; and

select from the high priority packets until said high priority packets are exhausted.

39. The article of claim 38, wherein high priority packets comprise TC7 packets.

40. A system comprising:

a switched fabric; and

a node coupled to the switched fabric, the node including;

an interface to receive a plurality of packets from a plurality of packet queues, each packet queue corresponding to one virtual channel; and

a packet arbiter to determine if the plurality of packets include one or more high priority packets, and to select from the high priority packets until said high priority packets are exhausted.

41. The system of claim 40, wherein the switched fabric comprises an Advanced Switching network, and wherein the high priority packets comprise TC7 packets.