Throttled command completion time

• US 8,271,692 B1
• Filed: 10/01/2010
• Issued: 09/18/2012
• Est. Priority Date: 10/01/2010
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Barlow, Carl E., Tsai, Chun Sei, Dinh, Peter H., Viglione, Joseph M., Huynh, Sang
• Primary Examiner(s): Mamo, Elias
• Application Number:
  US12/895,851
• Time in Patent Office: 718 Days
• Field of Search: 710/5
• US Class Current: 710/5
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0676 Magnetic disk device

Abstract

A storage device comprising a storage media and a controller is disclosed. The controller is configured to receive access commands from a host, to write data to or read data from the storage media based on the access commands, to detect a trigger event, and, when the trigger event is detected, to throttle back the access commands from the host based on an amount of data in a cache.

Claims

1. A storage device, comprising:

a storage media; and

a controller configured to;

receive access commands from a host, to write data to or read data from the storage media based on the access commands;

determine a throttled command completion time based on an amount of data in a cache, wherein the throttled command completion time defines a time duration which the storage device does not receive a new access command from the host;

detect a trigger event; and

,

when the trigger event is detected, throttle back the access commands from the host by withholding a command completion status from the host for the duration of the throttled command completion time,

wherein the controller is configured to dynamically adjust the throttled command completion time based on changes in a command completion time limit from the host.

2. The storage device of claim 1, wherein the trigger event comprises a condition reducing performance of data writes to the storage media.

3. The storage device of claim 1, wherein the trigger event comprises a command instructing the controller to throttle back commands from the host.

4. The storage device of claim 1, wherein the trigger event comprises a background operation performed by the controller.

5. The storage device of claim 1, wherein the throttled command completion time is based on a percent of the cache that is full.

6. The storage device of claim 1, wherein the controller is configured to determine the throttled command completion time when the amount of data in the cache exceeds a threshold.

7. The storage device of claim 1, wherein the throttled command completion time is a linear function of the amount of data in the cache.

8. The storage device of claim 1, wherein the throttled command completion time is based on a maximum delay time allowed by the host for the storage device to complete an access command before the host asserts a time out.

9. The storage device of claim of 2, wherein the controller is configured to detect the condition based on a number of retries of data writes to the storage media.

10. The storage device of claim 2, further comprising a temperature sensor, wherein the controller is configured to detect the condition based on a temperature reading from the temperature sensor.

11. The storage device of claim 2, further comprising a disturbance sensor configured to detect shock or vibration in the storage device, wherein the controller is configured to detect the condition based on a reading from the disturbance sensor.

12. The storage device of claim 1, wherein the storage media comprises a disk.

13. A method of regulating a flow of access commands from a host to a storage device, comprising:

determining a throttled command completion time based on an amount of data in a cache, wherein the throttled command completion time defines a time duration which the storage device does not receive a new access command from the host;

detecting a trigger event; and

when the trigger event is detected, throttling back the access commands from the host by withholding a command completion status from the host for the duration of the throttled command completion time; and

dynamically adjusting the throttled command completion time based on changes in a command completion time limit from the host.

14. The method of claim 13, wherein the trigger event comprises a condition reducing performance of data writes to the storage media.

15. The method of claim 13, wherein the trigger event comprises a command specifying a reduction in write performance of the storage device.

16. The method of claim 13, wherein the throttled command completion time is based on a percent of the cache that is full.

17. The method of claim 13, wherein the throttled command completion time is based on a maximum delay time allowed by the host for the storage device to complete an access command before the host asserts a time out.

18. The method of claim 14, wherein the detecting the condition is based on a number of retries of data writes to the storage media.

19. The method of claim 14, wherein the detecting the condition is based on a temperature reading from a temperature sensor.

20. The method of claim 14, wherein the detecting the condition is based on a reading from a disturbance sensor configured to detect shock or vibration in the storage device.