Operation method of memory controller and operation method of storage device including the same
An operation method of a memory controller which is configured to control a nonvolatile memory device includes receiving a command from the outside, calculating a delay time based on a currently available write buffer, a previously available write buffer, and a reference value, and processing the command based on the delay time.
1. A method of operating a memory controller which is configured to control a nonvolatile memory device, the method comprising:
in response to receiving each write command from an external device, calculating a delay time required for the memory controller to increase a currently available size of a write buffer of the memory controller to at least a reference size, based on the currently available size of the write buffer, a previously available size of the write buffer processing a previous write command, and the reference size;
increasing the currently available size of the write buffer to at least the reference size during the delay time;
allocating space in the write buffer having at least the reference size; and
storing write data of the write command in the space in the write buffer.
2. The method of claim 1 , wherein the currently available size of the write buffer represents a first size of the write buffer at a first time point when the write command is received, and the previously available size of the write buffer represents a second size of write buffer before the first time point when the previous write command is received.
3. The method of claim 1 , wherein the delay time increases as the reference size minus the currently available size of the write buffer increases, and
wherein the delay time increases as the previously available size of the write buffer minus of the currently available size of the write buffer increases.
4. The method of claim 1 , wherein the write command is processed after the delay time has elapsed from a time point when the write command is received.
5. The method of claim 1 , further comprising:
if the currently available size of the write buffer is greater than the reference size or the delay time is smaller than a specific value, allocating the space in the write buffer and storing the write data of the write command in the space of the write buffer without increasing the currently available size of the write buffer to at least the reference size.
6. The method of claim 5 , further comprising:
transmitting a response to the write command to the external device, after storing the write data of the write command in the space of the write buffer.
7. The method of claim 5 , further comprising:
writing the write data stored in the space in the write buffer to the nonvolatile memory device.
8. The method of claim 1 , further comprising queuing the write command received from the external device in a command queue.
9. A method of operating a memory controller which is configured to control a nonvolatile memory device, the method comprising:
in response to receiving each write command from an external device, calculating a first delay time required for the memory controller to increase a currently available size of a write buffer of the memory controller to at least a reference size, based on the currently available size of the write buffer, a previously available size of the write buffer, and the reference size;
calculating a maximum delay time based on a write buffer release rate representing a difference between a first amount of the write buffer released per unit time and a second amount of the write buffer allocated per unit time;
if the first delay time is greater than the maximum delay time, increasing the currently available size of the write buffer to at least the reference size during the maximum delay time;
if the first delay time is less than the maximum delay time, increasing the currently available size of the write buffer to at least the reference size during the delay time;
allocating space in the write buffer having at least the reference size; and
storing write data of the write command in the space in the write buffer.
10. The method of claim 9 , wherein the write buffer release rate decreases if a maintenance operation is performed on the nonvolatile memory device.
11. The method of claim 10 , wherein the maximum delay time decreases as the first amount of the write buffer release rate increases.
12. The method of claim 9 , wherein the first delay time increases as the reference size minus the currently available size of the write buffer increases, and
wherein the first delay time increases as the previously available size of the write buffer minus the currently available size of the write buffer increases.
13. The method of claim 9 , further comprising:
if the first delay time is greater than the maximum delay time, allocating the space in the write buffer and storing the write data of the write command in the space of the write buffer without increasing the currently available size of the write buffer to at least the reference size before the maximum delay time has elapsed; and
if the first delay time is not greater than the maximum delay time, allocating the space in the write buffer and storing the write data of the write command in the space of the write buffer without increasing the currently available size of the write buffer to at least the reference size after the first delay time has elapsed.
14. The method of claim 9 , further comprising:
if the currently available size of the write buffer is greater than the reference size or the first delay time is smaller than a specific value, allocating the space in the write buffer and storing the write data of the write command in the space of the write buffer without increasing the currently available size of the write buffer to at least the reference size.