Memory control method, memory storage device, and memory control circuit unit

1 . A memory control method for a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module comprises a plurality of physical units, the memory control method comprising:

judging a load level of the rewritable non-volatile memory module;

determining a suspend interval between a plurality of suspend commands according to the load level; and

sequentially issuing the suspend commands to the rewritable non-volatile memory module according to the suspend interval, wherein the suspend commands are configured to suspend an operation currently executed by the rewritable non-volatile memory module to execute a read operation, wherein a time interval from an end of the read operation to receiving a next one of the suspend commands is longer than or equal to the suspend interval.

2 . The memory control method according to claim 1 , further comprising:

judging whether the load level of the rewritable non-volatile memory module is a light load or a heavy load,

wherein the step of determining the suspend interval between the suspend commands according to the load level comprises:

if the load level is the light load, reducing the suspend interval; and

if the load level is the heavy load, increasing the suspend interval.

3 . The memory control method according to claim 2 , wherein the operation is an erase operation, the suspend interval is an erase suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a write command from a host system, and storing the write command in a buffer memory;

when a free memory space of the buffer memory is greater than or equal to a first buffer threshold, judging the load level to be the light load; and

when the free memory space of the buffer memory is less than or equal to a second buffer threshold, judging the load level to be the heavy load, wherein the second buffer threshold is less than the first buffer threshold.

4 . The memory control method according to claim 3 , further comprising:

when the free memory space of the buffer memory is less than the first buffer threshold and greater than the second buffer threshold, maintaining the suspend interval unchanged.

5 . The memory control method according to claim 2 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a command from a host system, and adding the command to a command queue;

if an occupancy rate of the command queue is greater than a first queue threshold, judging the load level to be the heavy load; and

if the occupancy rate of the command queue is less than a second queue threshold, judging the load level to be the light load.

6 . The memory control method according to claim 2 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

calculating a write speed of a host system;

if the write speed is less than a first write speed threshold, judging the load level to be the light load; and

if the write speed is greater than a second write speed threshold, judging the load level to be the heavy load.

7 . The memory control method according to claim 1 , wherein when the rewritable non-volatile memory module returns to the operation from one of the suspend commands, the rewritable non-volatile memory module executes the operation after a warm-up time, the memory control method further comprising:

in response to a number of a plurality of read commands issued by a host system being greater than a number of a plurality of write commands, setting the suspend interval to be shorter than the warm-up time.

8 . A memory storage device, comprising:

a connection interface unit, configured to couple to a host system;

a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module comprises a plurality of physical units; and

a memory control circuit unit, coupled to the connection interface unit and the rewritable non-volatile memory module,

wherein the memory control circuit unit is configured to execute a plurality of steps of:

judging a load level of the rewritable non-volatile memory module;

determining a suspend interval between a plurality of suspend commands according to the load level; and

sequentially issuing the suspend commands to the rewritable non-volatile memory module according to the suspend interval, wherein the suspend commands are configured to suspend an operation currently executed by the rewritable non-volatile memory module to execute a read operation, wherein a time interval from an end of the read operation to receiving a next one of the suspend commands is longer than or equal to the suspend interval.

9 . The memory storage device according to claim 8 , wherein the steps further comprise:

judging whether the load level of the rewritable non-volatile memory module is a light load or a heavy load,

wherein the step of determining the suspend interval between the suspend commands according to the load level comprises:

if the load level is the light load, reducing the suspend interval; and

if the load level is the heavy load, increasing the suspend interval.

10 . The memory storage device according to claim 9 , wherein the operation is an erase operation, the suspend interval is an erase suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a write command from the host system, and storing the write command in a buffer memory;

when a free memory space of the buffer memory is greater than or equal to a first buffer threshold, judging the load level to be the light load; and

when the free memory space of the buffer memory is less than or equal to a second buffer threshold, judging the load level to be the heavy load, wherein the second buffer threshold is less than the first buffer threshold.

11 . The memory storage device according to claim 10 , wherein the steps further comprise:

when the free memory space of the buffer memory is less than the first buffer threshold and greater than the second buffer threshold, maintaining the suspend interval unchanged.

12 . The memory storage device according to claim 9 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a command from the host system, and adding the command to a command queue;

if an occupancy rate of the command queue is greater than a first queue threshold, judging the load level to be the heavy load; and

if the occupancy rate of the command queue is less than a second queue threshold, judging the load level to be the light load.

13 . The memory storage device according to claim 9 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

calculating a write speed of the host system;

if the write speed is less than a first write speed threshold, judging the load level to be the light load; and

if the write speed is greater than a second write speed threshold, judging the load level to be the heavy load.

14 . The memory storage device according to claim 8 , wherein when the rewritable non-volatile memory module returns to the operation from one of the suspend commands, the rewritable non-volatile memory module executes the operation after a warm-up time, and the steps further comprise:

in response to a number of a plurality of read commands issued by the host system being greater than a number of a plurality of write commands, setting the suspend interval to be shorter than the warm-up time.

15 . A memory control circuit unit, configured to control a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module comprises a plurality of physical units, and the memory control circuit unit comprises:

a host interface, configured to couple to a host system;

a memory interface, configured to couple to the rewritable non-volatile memory module;

a memory management circuit, coupled to the host interface and the memory interface,

wherein the memory management circuit is configured to execute a plurality of steps of:

judging a load level of the rewritable non-volatile memory module;

determining a suspend interval between a plurality of suspend commands according to the load level; and

sequentially issuing the suspend commands to the rewritable non-volatile memory module according to the suspend interval, wherein the suspend commands are configured to suspend an operation currently executed by the rewritable non-volatile memory module to execute a read operation, wherein a time interval from an end of the read operation to receiving a next one of the suspend commands is longer than or equal to the suspend interval.

16 . The memory control circuit unit according to claim 15 , wherein the steps further comprise:

judging whether the load level of the rewritable non-volatile memory module is a light load or a heavy load,

wherein the step of determining the suspend interval between the suspend commands according to the load level comprises:

if the load level is the light load, reducing the suspend interval; and

if the load level is the heavy load, increasing the suspend interval.

17 . The memory control circuit unit according to claim 16 , wherein the operation is an erase operation, the suspend interval is an erase suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a write command from the host system, and storing the write command in a buffer memory;

when a free memory space of the buffer memory is greater than or equal to a first buffer threshold, judging the load level to be the light load; and

when the free memory space of the buffer memory is less than or equal to a second buffer threshold, judging the load level to be the heavy load, wherein the second buffer threshold is less than the first buffer threshold.

18 . The memory control circuit unit according to claim 17 , wherein the steps further comprise:

when the free memory space of the buffer memory is less than the first buffer threshold and greater than the second buffer threshold, maintaining the suspend interval unchanged.

19 . The memory control circuit unit according to claim 16 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

receiving a command from the host system, and adding the command to a command queue;

if an occupancy rate of the command queue is greater than a first queue threshold, judging the load level to be the heavy load; and

if the occupancy rate of the command queue is less than a second queue threshold, judging the load level to be the light load.

20 . The memory control circuit unit according to claim 16 , wherein the operation is a write operation, the suspend interval is a write suspend interval, and the step of judging whether the load level of the rewritable non-volatile memory module is the light load or the heavy load comprises:

calculating a write speed of the host system;

if the write speed is less than a first write speed threshold, judging the load level to be the light load; and

if the write speed is greater than a second write speed threshold, judging the load level to be the heavy load.

21 . The memory control circuit unit according to claim 15 , wherein when the rewritable non-volatile memory module returns to the operation from one of the suspend commands, the rewritable non-volatile memory module executes the operation after a warm-up time, and the steps further comprise:

in response to a number of a plurality of read commands issued by the host system being greater than a number of a plurality of write commands, setting the suspend interval to be shorter than the warm-up time.