Using host transfer rates to select a recording medium transfer rate for transferring data to a recording medium

• US 9,043,508 B2
• Filed: 10/25/2012
• Issued: 05/26/2015
• Est. Priority Date: 10/27/2011
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Ohta, Yumiko, Oishi, Yutaka
• Primary Examiner(s): Park, Ilwoo
• Application Number:
  US13/660,951
• Publication Number:
  US 20130111080A1
• Time in Patent Office: 943 Days
• US Class Current: 710/29
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0674 Disk device
• CPC Class Codes: G06F 3/0682 Tape device
• CPC Class Codes: G11B 2020/1062 Data buffering arrangements, e.g. recording or playback buffers
• CPC Class Codes: G11B 2020/10814 involving specific measures to prevent a buffer underrun
• CPC Class Codes: G11B 2220/90 Tape-like record carriers
• CPC Class Codes: G11B 5/00813 magnetic tapes

Abstract

Provided are a storage device, controller, and method for using host transfer rates to select a recording medium transfer rate for transferring data to a recording medium. A host transfer rate of data with respect to a buffer is measured. Provided are a plurality of recording medium transfer rates at which data is transferred between the buffer and the recording medium. A determination is made of an amount of decrease in the host transfer rate. The recording medium transfer rate is selected based on the amount of decrease in the host transfer rate. A transfer rate at which the storage device transfers data is set to the selected recording medium transfer rate.

Claims

1. A storage device in communication with a host, comprising:

a buffer for temporarily storing data transferred between the host and the storage device;

a recording medium to store data;

a controller for controlling transfer of data between the buffer and the recording medium by performing operations, the operations comprising;

measuring a host transfer rate of data with respect to the buffer;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer to the recording medium;

determining an amount of decrease in the host transfer rate;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate, wherein for the host transfer rate less than a first rate, the recording medium transfer rate is not adjusted, wherein for the host transfer rate greater than the first rate and less than a second rate, the recording medium transfer rate is reduced to a first transfer rate, and wherein for the host transfer rate greater than the second rate, the recording medium transfer rate is reduced to a second transfer rate less than the first transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

2. The storage device of claim 1, wherein each of the recording medium transfer rates is associated with one of a plurality of index values, wherein the operations further comprise:

determining one of the index values corresponding to the determined amount of decrease in the host transfer rate, wherein the selected recoding medium transfer rate is associated with the determined index value.

3. The storage device of claim 2, wherein the recording medium transfer rates associated with higher index values have slower transfer rates, wherein each of the index values is associated with a range of decreases in the host transfer rate, and wherein determining the index value comprises determining the index value associated with the range of decreases in the host transfer rates including the determined amount of decrease in the host transfer rate.

4. The storage device of claim 1, wherein the amount of decreases in the host transfer rate is a function of an average host transfer rate and a current measured host transfer rate.

5. A storage device in communication with a host, comprising:

a buffer for temporarily storing data transferred between the host and the storage device;

a recording medium to store data;

a controller for controlling transfer of data between the buffer and the recording medium by performing operations, the operations comprising;

measuring a host transfer rate of data with respect to the buffer;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer to the recording medium;

determining an amount of decrease in the host transfer rate;

determining a data size transferred at the decreasing host transfer rate;

determining a ratio of the determined data size to measured samples;

determining whether the ratio of the determined data size is below a data size ratio;

in response to determining that the ratio of determined data size falls below the data size ratio, performing;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

6. A controller implementing a program in a storage device coupled to a host, wherein the storage device has a recording medium and a buffer to buffer data transferred between the host and the recording medium, wherein the program is executed to cause the controller to perform operations comprising:

measuring a host transfer rate of data with respect to the buffer;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer and the recording medium;

determining an amount of decrease in the host transfer rate;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate, wherein for the host transfer rate less than a first rate, the recording medium transfer rate is not adjusted, wherein for the host transfer rate greater than the first rate and less than a second rate, the recording medium transfer rate is reduced to a first transfer rate, and wherein for the host transfer rate greater than the second rate, the recording medium transfer rate is reduced to a second transfer rate less than the first transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

7. The controller of claim 6, wherein each of the recording medium transfer rates is associated with one of a plurality of index values, wherein the operations further comprise:

determining one of the index values corresponding to the determined amount of decrease in the host transfer rate, wherein the selected recoding medium transfer rate is associated with the determined index value.

8. The controller of claim 7, wherein the recording medium transfer rates associated with higher index values have slower transfer rates, wherein each of the index values is associated with a range of decreases in the host transfer rate, and wherein determining the index value comprises determining the index value associated with the range of decreases in the host transfer rates including the determined amount of decrease in the host transfer rate.

9. The controller of claim 6, wherein the amount of decreases in the host transfer rate is a function of an average host transfer rate and a current measured host transfer rate.

10. The controller of to claim 6, wherein the controller includes:

a measurement section for measuring a plurality of host transfer rates for exchanging data with the higher-level apparatus;

an adjustment section for adjusting the recording medium transfer rate for exchanging the data with the recording medium to approximate the drive recording medium transfer rate to the host transfer rate;

a determination section for determining whether measured host transfer rates have a decrease with respect to an average host transfer rate to indicate that the host transfer rate is intermittently decreasing; and

a selection section for selecting a drive transfer rate based on the determination whether the host transfer rate is intermittently decreasing to reduce the drive transfer rate.

11. The controller of claim 10, wherein the measurement section measures a plurality of samples of times of increases or decreases in a fixed data size in the buffer to calculate the host transfer rate.

12. A controller implementing a program in a storage device coupled to a host, wherein the storage device has a recording medium and a buffer to buffer transferred between the host and the recording medium, wherein the program is executed to cause the controller to perform operations comprising:

measuring a host transfer rate of data with respect to the buffer;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer and the recording medium;

determining an amount of decrease in the host transfer rate;

determining a data size transferred at the decreasing host transfer rate;

determining a ratio of the determined data size to measured samples;

determining whether the ratio of the determined data size is below a data size ratio;

in response to determining that the ratio of determined data size falls below the data size ratio, performing;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

13. The controller of claim 12, wherein the data size ratio is 3% or 10%.

14. A method, comprising:

measuring a host transfer rate of data with respect to a buffer in a storage device that buffer data transferred between a recording medium and a host;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer to the recording medium;

determining an amount of decrease in the host transfer rate;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate, wherein for the host transfer rate less than a first rate, the recording medium transfer rate is not adjusted, wherein for the host transfer rate greater than the first rate and less than a second rate, the recording medium transfer rate is reduced to a first transfer rate, and wherein for the host transfer rate greater than the second rate, the recording medium transfer rate is reduced to a second transfer rate less than the first transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

15. The method of claim 14, wherein each of the recording medium transfer rates is associated with one of a plurality of index values, further comprising:

determining one of the index values corresponding to the determined amount of decrease in the host transfer rate, wherein the selected recoding medium transfer rate is associated with the determined index value.

16. The method of claim 15, wherein the recording medium transfer rates associated with higher index values have slower transfer rates, wherein each of the index values is associated with a range of decreases in the host transfer rate, and wherein determining the index value comprises determining the index value associated with the range of decreases in the host transfer rates including the determined amount of decrease in the host transfer rate.

17. The method of claim 14, wherein the amount of decreases in the host transfer rate is a function of an average host transfer rate and a current measured host transfer rate.

18. A method, comprising:

measuring a host transfer rate of data with respect to a buffer in a storage device that buffer data transferred between a recording medium and a host;

providing a plurality of recording medium transfer rates at which data is transferred between the buffer to the recording medium;

determining an amount of decrease in the host transfer rate;

determining a data size transferred at the decreasing host transfer rate;

determining a ratio of the determined data size to measured samples;

determining whether the ratio of the determined data size is below a data size ratio;

in response to determining that the ratio of determined data size falls below the data size ratio, performing;

selecting the recording medium transfer rate based on the amount of decrease in the host transfer rate; and

setting a transfer rate in the storage device at which data is transferred to the selected recording medium transfer rate.

19. The method of claim 18, wherein the data size ratio is 3% or 10%.