US 2024/0256455 A1Published application

Enhanced Read Cache for Stream Switching in Storage Device

AssigneeWestern Digital Technologies, Inc.

InventorsSangyun JUNG, Minwoo LEE, Minyoung KIM

Life of this patent

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Abstract

In a data storage device, a controller can efficiently allocate a limited cache space to service multiple data streams. In one or more examples, in response to receiving a first read command for a first stream, the controller may respond to read commands for the first stream based on prefetching data for the first stream using buffers. When the controller receives a second read command for a second stream, the controller may respond to read commands based on prefetching data for the first stream and the second stream using the buffers. After receiving the second read command, in response to receiving a number of read commands for the first stream, the controller may cease prefetching data for the second stream using the buffers, and revert to responding to read commands for the first stream based on prefetching data for the first stream using the buffers.

Claims20

Dependent claims

A data storage device, comprising:

a host interface for coupling the data storage device to a host system;
a device memory;
a read cache including a plurality of buffers, each buffer configured to store data prefetched from the device memory for a stream of a plurality of streams;
and
a controller configured to:
receive a first read command for a first stream;
in response to receiving the first read command, respond to read commands for the first stream based on prefetching data for the first stream using the plurality of buffers;
receive a second read command for a second stream;
in response to receiving the second read command, respond to read commands for the first stream and the second stream based on prefetching data for the first stream and the second stream using the plurality of buffers;
and
after receiving the second read command for the second stream, in response to receiving a predetermined number of read commands for the first stream:
(i) cease to prefetch data for the second stream using the plurality of buffers, and (ii) revert to respond to read commands for the first stream based on prefetching data for the first stream using the plurality of buffers.

9 more elements

A method implemented using one or more controllers for one or more data storage devices, the method comprising:

receiving a first read command for a first stream;
in response to receiving the first read command, responding to read commands for the first stream based on prefetching data for the first stream using a plurality of buffers;
receiving a second read command for a second stream;
in response to receiving the second read command, responding to read commands for the first stream and the second stream based on prefetching data for the first stream and the second stream using the plurality of buffers;
and
after receiving the second read command for the second stream, in response to receiving a predetermined number of read commands for the first stream:
(i) ceasing to prefetch data for the second stream using the plurality of buffers, and (ii) reverting to respond to read commands for the first stream based on prefetching data for the first stream using the plurality of buffers.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/353,035Filed 14 Jul 2023
Priority: 30 Jan 2023
Published: 1 Aug 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G06F 12/0862
Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches: with prefetch
G06F 12/0868
For peripheral storage systems, e.g. disk cache: data transfer between cache memory and other subsystems, e.g. storage devices or host systems
G06F
Computing and data processing