SYSTEM AND METHOD FOR PROVIDING CONSISTENT, RELIABLE, AND PREDICTABLE PERFORMANCE IN A STORAGE DEVICE
The solution described here is a method to provide consistent performance in a storage device. A performance manager module is implemented to measure the time interval in which a command takes to be completed. In case the time interval is longer than a certain threshold, the difference is annotated and used on the consecutive commands within a programmable time window. This time window can be a regular time interval e.g. every second. In case the time interval is shorter than a threshold, the control module delays sending the command completion to the host until the threshold value is reached. The delay is adjusted based on the credit annotation due to commands that took longer than the time interval to be completed in order to compensate for commands that took longer than the threshold to complete, during a certain time window.
1 . An SSD storage device that uses a performance manager module.
2 . The SSD of claim 1 where the performance manager module is implemented in Hardware.
3 . The SSD of claim 1 where the threshold value are based on the worst case performance.
4 . The SSD of claim 2 where the performance manager adjusts the completion time based on the previous command history.
5 . The SSD of claim 2 where the threshold values are based on the command size.
6 . The SSD of claim 2 where the threshold values are based on the command type.
7 . The SSD of claim 2 where the performance manager module notifies the SSD control when the performance varies above or below a certain threshold from the average performance with a programmable window.
8 . The SSD of claim 1 where the performance manager module is implemented in Firmware.
9 . The SSD of claim 7 where the performance manager adjusts the completion time based on the previous command history.
10 . The SSD of claim 7 where the threshold values are based on the command size.
11 . The SSD of claim 7 where the threshold values are based on the command type.
12 . The SSD of claim 7 where the performance manager module notifies the controller when the performance varies above or below a certain threshold from the average performance with a programmable window.