Methods and apparatus for communicating low-latency word category over multi-lane link

1. An integrated circuit configured to communicate a low-latency word category over a bi-directional multi-lane link, the integrated circuit comprising:

a transmitter that transmits a first plurality of words over the multi-lane link to a receiver of another integrated circuit;

a transmitter controller that sends words of the first plurality of words that belong to the low-latency word category only over a designated lane of the multi-lane link and stripes words of the first plurality of words that belong to non-low-latency word categories over next available lanes of the multi-lane link;

a receiver that receives a second plurality of words over the multi-lane link from a transmitter of the other integrated circuit; and

a receiver controller that

determines a word category of a word in the second plurality of words,

responsive to a determination that the word is of the low-latency word category, reads the word from the designated lane before lane-to-lane deskew is completed, and

responsive to a determination that the word is of a non-low-latency word category, reads the word received from the designated lane after lane-to-lane deskew is completed.

2. The integrated circuit of claim 1 , wherein the low-latency word category comprises control words.

3. The integrated circuit of claim 2 , wherein the control words are utilized by higher layer protocols.

4. The integrated circuit of claim 2 , wherein the non-low-latency word categories comprises data words.

5. The integrated circuit of claim 2 , wherein the low-latency word category includes control words from shorter control codes, and wherein the non-low-latency word categories include control words from longer control codes.

6. The integrated circuit of claim 2 , wherein the low-latency word category comprises single-word control codes.

7. The integrated circuit of claim 6 , wherein the low-latency word category includes multiple-word control codes.

8. The integrated circuit of claim 1 , wherein the receiver controller is further configured to read words of the second plurality of words that are received over lanes other than the designated lane after lane-to-lane deskew is completed.

9. The integrated circuit of claim 1 , wherein the lanes of the multi-lane link have measurable latencies, and wherein the designated lane is configured for low-latency.

10. The integrated circuit of claim 9 , wherein the designated lane is configured for low-latency by not using a deskew buffer.

11. The integrated circuit of claim 9 , wherein the designated lane is configured for low-latency by preferential routing to reduce skew.

12. A method of utilizing a bi-directional multi-lane link, the method comprising:

transmitting a first plurality of words, wherein words of the first plurality of words that belong to a predetermined word category are transmitted only over a designated lane of the multi-lane link;

striping words of the first plurality of words that belong to other word categories, other than the predetermined category, onto next available lanes of the multi-lane link;

determining a word category of a word in a second plurality of words received over the designated lane;

responsive to a determination that the word is of the predetermined word category, reading the word from the designated lane before lane-to-lane deskew is completed; and

responsive to a determination that the word is not of the predetermined word category, reading the word from the designated lane after lane-to-lane deskew is completed.

13. The method of claim 12 , wherein the low-latency word category comprises control words.

14. The method of claim 13 , wherein the control words are utilized by higher layer protocols.

15. The method of claim 13 , wherein the non-low-latency word categories comprises data words.

16. The method of claim 13 , wherein the low-latency word category includes control words from shorter control codes, and wherein the non-low-latency word categories include control words from longer control codes.

17. The method of claim 13 , wherein the low-latency word category comprises single-word control codes.

18. The method of claim 17 , wherein the low-latency word category includes multiple-word control codes.

19. The method of claim 12 further comprising:

reading words of the second plurality of words that are received over lanes other than the designated lane after lane-to-lane deskew is completed.

20. The method of claim 12 , wherein the lanes of the multi-lane link have measurable latencies, and wherein the designated lane is configured for low-latency.

21. The method of claim 20 , wherein the designated lane is configured for low-latency by not using a deskew buffer.

22. The method of claim 20 , wherein the designated lane is configured for low-latency by preferential routing to reduce skew.

23. A circuit configured for low-latency communication of a predetermined word category over a bi-directional multi-lane link, the circuit comprising:

a local receiver that receives words over the multi-lane link from a remote transmitter; and

a receiver controller that

determines a word category of a word received over a lane,

responsive to a determination that the word received is of the predetermined word category, reads the word from the lane before lane-to-lane deskew is completed, and

responsive to a determination that the word received is not of the predetermined word category, reads the word from the lane after lane-to-lane deskew is completed.

24. The circuit of claim 23 , wherein the lane is a designated lane, and wherein the words of the predetermined word category are only received over the designated lane.

25. The circuit of claim 23 , wherein all words of a control packet that is a multi-word control packet are received and interpreted prior to the lane-to-lane deskew being completed.