Flow control of large sequential host read commands based on a queue threshold
Aspects of a storage device are provided which use flow control to prevent stalling during processing of read requests for a large read command. A controller of the storage device receives a read command for data from a host device, stores in a queue read requests for a portion of the data, and reads the portion of the data from a memory based on the read requests. The controller may store other read requests in the queue for other portions of the data when a number of read requests in the queue does not meet a threshold. Otherwise, the controller refrains from storing other read requests in the queue for other portions of the data when the number of read requests in the queue meets the threshold. The controller may operate similarly with subsequent sequential commands, but may continue to store read requests in the queue for subsequent random commands.
1. A storage device, comprising:
a memory configured to store data; and
a controller configured to receive, from a host device, a first read command having a first command length for the data, to store at least one read request associated with the first read command into a queue for a portion of the data, and to read the portion of the data from the memory based on the at least one read request,
wherein the controller is further configured to store other read requests associated with the first read command into the queue for one or more other portions of the data when a number of read requests associated with the first read command in the queue does not meet a threshold, to refrain from storing the other read requests associated with the first read command into the queue when the number of read requests associated with the first read command in the queue meets the threshold, and to process a second read command having a second command length smaller than the first command length when the number of read requests associated with the first read command in the queue meets the threshold.
2. The storage device of claim 1 , wherein the controller is further configured, after receiving the first read command, to receive a third read command having a third command length that corresponds to the first command length for sequential data stored in the memory, and to refrain from storing one or more read requests associated with the third read command into the queue for the sequential data when the number of read requests associated with the first read command in the queue meets the threshold.
3. The storage device of claim 1 , wherein the controller is further configured, after receiving the first read command, to receive the second read command for random data stored in the memory, and to store one or more read requests associated with the second read command into the queue for the random data when the number of read requests associated with the first read command in the queue meets the threshold.
4. The storage device of claim 3 , wherein the controller is further configured to identify a physical address associated with the portion of the data based on a logical-to-physical (L2P) mapping table, and wherein the controller is further configured to store the one or more read requests associated with the second read command into the queue for the random data in response to identifying the physical address when the portion associated with the physical address is a last portion of the data.
5. The storage device of claim 1 , wherein the threshold is less than a maximum size for the queue.
6. The storage device of claim 1 , wherein the portion of the data is based on a rate at which the first read command is received from the host device.
7. The storage device of claim 1 , wherein the portion of the data is based on the first command length of the first read command.
8. A storage device, comprising:
a memory configured to store first data and second data; and
a controller configured to receive, from a host device, a first read command having a first command length for the first data, to receive, from the host device, a second read command having a second command length that corresponds to the first command length for the second data after receiving the first read command, to store at least one read request associated with the first read command into a queue for a portion of the first data, and to read the portion of the first data from the memory based on the at least one read request associated with the first read command,
wherein the controller is further configured to store one or more read requests associated with the second read command into the queue for the second data when a number of read requests associated with the first read command in the queue does not meet a threshold, to refrain from storing the one or more read requests associated with the second read command into the queue for the second data when the number of read requests associated with the first read command in the queue meets the threshold, and to process a third read command having a third command length smaller than the first command length when the number of read requests associated with the first read command in the queue meets the threshold.
9. The storage device of claim 8 , wherein the second data comprises sequential data.
10. The storage device of claim 8 , wherein the controller is further configured, after receiving the first read command and before receiving the second read command, to receive the third read command for random data stored in the memory, and to store at least one read request associated with the third read command into the queue for the random data when the number of read requests associated with the first read command in the queue meets the threshold.
11. The storage device of claim 10 , wherein the controller is further configured to identify a physical address associated with the portion of the first data based on a logical-to-physical (L2P) mapping table, and wherein the controller is further configured to store the one or more read requests associated with the third read command into the queue for the random data in response to identifying the physical address when the portion associated with the physical address is a last portion of the first data.
12. The storage device of claim 8 , wherein the threshold is less than a maximum size for the queue.
13. The storage device of claim 8 , wherein the portion of the first data is based on a rate at which the first read command is received from the host device.
14. The storage device of claim 8 , wherein the portion of the first data is based on the first command length of the first read command.
15. A storage device, comprising:
a memory configured to store first data and second data; and
a controller configured to receive, from a host device, a first read command having a first command length for the first data, to receive, from the host device, a second read command having a second command length smaller than the first command length for the second data after receiving the first read command, to store at least one read request associated with the first read command into a queue for a portion of the first data, and to read the portion of the first data from the memory based on the at least one read request associated with the first read command,
wherein the controller is further configured to refrain from storing other read requests associated with the first read command into the queue and process the second read command by storing at least one read request associated with the second read command into the queue for the second data, when a number of read requests associated with the first read command in the queue meets a threshold.
16. The storage device of claim 15 , wherein the second data comprises random data.
17. The storage device of claim 15 , wherein the controller is further configured, after receiving the first read command and before receiving the second read command, to receive a third read command for sequential data stored in the memory, and to refrain from storing at least one read request associated with the third read command into the queue for the sequential data when the number of read requests associated with the first read command in the queue meets the threshold.
18. The storage device of claim 15 , wherein the controller is further configured to identify a physical address associated with the portion of the first data based on a logical-to-physical (L2P) mapping table, and wherein the controller is further configured to store the at least one read request associated with the second read command into the queue for the second data in response to identifying the physical address when the portion associated with the physical address is a last portion of the first data.
19. The storage device of claim 15 , wherein the threshold is less than a maximum size for the queue.
20. The storage device of claim 15 , wherein the portion of the first data is based on at least one of a rate at which the first read command is received from the host device or the first command length of the first read command.