SSD Controller Pre-Suspend Adjacent Data Read
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Solution Overview
Problem
Current solid-state drives (SSDs) face performance degradation due to command collisions, where multiple commands compete for shared resources, leading to pending states until all resources are available, often requiring a sequential pipeline approach.
Innovation Solution
Implementing a pre-suspend processing method where the controller directs the SSD to read adjacent data to a target location and store it in a read cache, delaying the write command to utilize resources already allocated for the write operation, thereby reducing collisions by dedicating resources for the write command before execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sequential pipeline approach is used to handle multiple commands, then resource conflicts are avoided, but command processing speed and productivity deteriorate
Solution Approach 1:
The patent applies preliminary action by performing read operations before write operations when resources are pre-allocated. The controller identifies pending read commands and executes them prior to executing write commands, utilizing the pre-allocated resources efficiently. This resolves the contradiction by maintaining resource conflict avoidance while improving command processing throughput through better resource utilization.
Solution Approach 2:
The patent implements dynamics by dynamically adjusting command execution order based on resource allocation status. The controller monitors resource availability and dynamically schedules read and write commands to maximize throughput without causing conflicts. This dynamic scheduling approach allows the system to adapt to varying workloads and resource states, improving productivity while maintaining reliability.
2Productivity
If multiple commands compete for shared resources simultaneously, then command processing parallelism is improved, but command collisions and pending states increase
Solution Approach 1:
The patent applies preliminary action by pre-allocating resources for write commands before they are executed. The controller identifies upcoming write commands and reserves necessary resources in advance, then uses these pre-allocated resources to execute associated read commands without causing collisions. This eliminates waiting time while maintaining parallelism.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a resource allocation manager that mediates between read and write commands. This intermediary pre-allocates resources and coordinates command execution to prevent collisions, allowing multiple commands to proceed in parallel without conflicting for shared resources, thus reducing pending states and waiting time.
3Adaptability or versatility
If resources are allocated dynamically during command execution, then resource utilization flexibility is improved, but command execution time and loss of time increase
Solution Approach 1:
The patent applies preliminary action by pre-allocating resources for write commands before execution. The controller identifies pending write commands and reserves necessary resources in advance, eliminating the need for dynamic allocation during execution. This reduces command execution time while maintaining the flexibility to handle varying workload patterns through intelligent pre-allocation strategies.
Data Source
AI summary
Method and apparatus for managing data in a storage device, such as a solid-state drive (SSD). An apparatus includes a main non-volatile memory (NVM) such as a NAND flash memory. A host command queue lists pending data transfer commands to transfer data between the NVM and a host. For each write command received by the NVM to store write data to an associated target location, a controller examines the host command queue. Based on this review, the controller may direct the NVM to read data adjacent the associated target location to which data are to be written by the write command and to transfer the read data to a read cache. The read data may use some or all of the same resources used to store the write data to the NVM. The read data may be subsequently transferred from the read cache to the host.