Granted Patent B2

US 8,069,285 · App. 12/347,783 · Granted Nov 29, 2011

Abstract

Claims (72)

1. A method for improving communication throughput of a link between Serial Attached SCSI (SAS) / Serial ATA (SATA) devices, wherein at least one counter is associated with the link, the method comprising:

establishing the link at a first signal rate;

incrementing one of the at least one counter based on an error sensed on the link;

determining, based on the at least one counter, whether to maintain the first signal rate;

re-establishing the link at a second signal rate based on the determination;

wherein the second signal rate is lower than the first signal rate; and

wherein the link is one of a SATA link and a SAS link;

resetting at least one of the at least one counter;

incrementing one of the at least one counter based on another error sensed on the link;

determining that the lower signal rate encounters a similar amount of errors as the first signal rate, based on the least one counter; and

re-establishing the link at the first signal rate based on the determination.

2. The method of claim 1 , wherein each of the SAS/SATA devices is one of a SATA controller, a SAS controller, a SATA drive, a SAS drive, and a SAS expander.

3. The method of claim 1 , wherein a type of the error is one of invalid dword, running disparity error, and PHY reset problem.

4. The method of claim 1 , wherein the first signal rate is selected from 12 Gbps, 6 Gbps, and 3 Gbps, and wherein the second signal rate is selected from 6 Gbps, 3 Gbps, and 1.5 Gbps.

5. The method of claim 1 , wherein the determining step comprises checking whether one of the at least one counter exceeds a pre-defined value.

6. The method of claim 1 , wherein the determining step comprises checking whether a change within one of the at least one counter over a time period exceeds a pre-defined value.

7. The method of claim 1 , wherein the error is a first error, the method further comprising:

incrementing one of the at least one counter based on a second error sensed on the link;

determining, based on the at least one counter, whether to maintain the second signal rate; and

re-establishing the link at a third signal rate based on the determination;

wherein the third signal rate is lower than the second signal rate.

8. The method of claim 7 , wherein:

determining whether to maintain the first signal rate comprises checking whether one of the at least one counter exceeds a first pre-defined value;

determining whether to maintain the second signal rate comprises checking whether the one of the at least one counter exceeds a second pre-defined value; and

the first pre-defined value is greater than or equal to the second pre-defined value.

9. The method of claim 1 , wherein the lower signal rate comprises a lowest signal rate for the link.

10. The method of claim 1 , further comprising sending a message from a first SAS/SATA device to a second SAS/SATA device, wherein the determining step is performed at the first SAS/SATA device, and wherein the re-establishing step comprises re-establishing the link from the second SAS/SATA device to a third SAS/SATA device based on the message.

11. A Serial Attached SCSI (SAS) / Serial ATA (SATA) device for improving communication throughput of a link with another SAS/SATA device, wherein at least one counter is associated with the link, the SAS/SATA device comprising:

the at least one counter;

an establishing element for establishing the link at a first signal rate;

an incrementing element for incrementing one of the at least one counter based on an error sensed on the link;

a determining element for determining, based on the at least one counter, whether to maintain the first signal rate;

a resetting element for resetting the one of the at least one counter and

a re-establishing element for re-establishing the link at a second signal rate based on the determination;

wherein the second signal rate is lower than the first signal rate;

wherein the link is one of a SATA link and a SAS link;

wherein the incrementing element is further adapted for incrementing at least one of the at least one counter based on another error sensed on the link;

wherein the determining element is further adapted for determining that the lower signal rate encounters a similar amount of errors as the first signal rate, based on the least one counter; and

wherein the re-establishing element is further adapted for re-establishing the link at the first signal rate based on the determination.

12. The SAS/SATA device of claim 11 , wherein each of the SAS/SATA devices is one of a SATA controller, a SAS controller, a SATA drive, a SAS drive, and a SAS expander.

13. The SAS/SATA device of claim 11 , wherein a type of the error is one of invalid dword, running disparity error, and PHY reset problem.

14. The SAS/SATA device of claim 11 , wherein the first signal rate is selected from 12 Gbps, 6 Gbps, and 3 Gbps, and wherein the second signal rate is selected from 6 Gbps, 3 Gbps, and 1.5 Gbps.

15. The SAS/SATA device of claim 11 , wherein the determining element is further adapted for checking whether one of the at least one counter exceeds a pre-defined value.

16. The SAS/SATA device of claim 11 , wherein the determining element is further adapted for checking whether a change within one of the at least one counter over a time period exceeds a pre-defined value.

17. The SAS/SATA device of claim 11 , wherein the error is a first error, wherein:

the incrementing element is further adapted for incrementing one of the at least one counter based on a second error sensed on the link;

the determining element is further adapted for determining, based on the at least one counter, whether to maintain the second signal rate; and

the re-establishing element is further adapted for re-establishing the link at a third signal rate based on the determination;

wherein the third signal rate is lower than the second signal rate.

18. The SAS/SATA device of claim 17 , wherein:

determining whether to maintain the first signal rate comprises checking whether one of the at least one counter exceeds a first pre-defined value;

determining whether to maintain the second signal rate comprises checking whether the one of the at least one counter exceeds a second pre-defined value; and

the first pre-defined value is greater than or equal to the second pre-defined value.

19. The SAS/SATA device of claim 11 , wherein the lower signal rate comprises a lowest signal rate for the link.

20. A system for improving communication throughput of a link between Serial Attached SCSI (SAS) / Serial ATA (SATA) devices, wherein at least one counter is associated with the link, the system comprising:

a first SAS/SATA device comprising:

the at least one counter;

an incrementing element for incrementing one of the at least one counter based on an error sensed on the link;

a determining element for determining, based on the at least one counter, whether to maintain a first signal rate;

a resetting element for resetting the one of the at least one counter; and

a sending element for sending a message from the first SAS/SATA device to a second SAS/SATA device based on the determination;

the second SAS/SATA device; and

a third SAS/SATA device;

wherein the second SAS/SATA device comprises:

an establishing element for establishing the link to the third SAS/SATA device at the first signal rate;

a receiving element for receiving the message; and

a re-establishing element for re-establishing the link at a second signal rate to the third SAS/SATA device based on the message;

wherein the second signal rate is lower than the first signal rate;

wherein the link is one of a SATA link and a SAS link;

wherein the incrementing element is further adapted for incrementing at least one of the at least one counter based on another error sensed on the link;

wherein the determining element is further adapted for determining that the lower signal rate encounters a similar amount of errors as the first signal rate, based on the least one counter; and

wherein the re-establishing element is further adapted for re-establishing the link at the first signal rate based on the determination.

Assignments (9)