Host-Accessible Prefetcher Queue for Mixed-Memory Latency
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Solution Overview
Problem
Existing storage devices experience varying latencies due to the use of different storage media, such as volatile and non-volatile memory, which can hinder overall system performance and responsiveness.
Innovation Solution
Implementing a prefetching mechanism that moves data from non-volatile memory to faster volatile memory using a prefetch request queue, managed by the operating system or multiple queues to reduce contention, and optimizing prefetch stride for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If data is stored in non-volatile memory, then data persistence is improved, but access latency increases
Solution Approach 1:
The system performs preliminary actions by prefetching data from non-volatile memory to volatile memory before it is actually needed by the application. The host-accessible prefetcher queue allows the host to proactively specify which data should be prefetched, enabling the storage device to retrieve and transfer data in advance, thus reducing access latency when the data is subsequently needed.
Solution Approach 2:
The patent introduces volatile memory as an intermediary between non-volatile memory and the host system. Data is first transferred from non-volatile memory to volatile memory (which has faster access times), and then accessed by the host. This intermediary layer resolves the contradiction by providing fast access to frequently needed data while maintaining the persistence benefits of non-volatile memory.
2Loss of time
If prefetching is implemented, then access latency is reduced, but system complexity increases
Solution Approach 1:
The host-accessible prefetcher queue serves as an intermediary mechanism that simplifies the prefetching process. Instead of implementing complex autonomous prefetching logic in the storage device, the system uses a simple queue structure that the host can directly access and populate with prefetch requests. This approach reduces access latency while keeping the system complexity manageable by leveraging the host's existing capabilities.
Solution Approach 2:
The host system serves itself by directly managing the prefetcher queue without requiring complex storage device intervention. The host can independently specify prefetch requests, manage the queue, and coordinate with the storage device, thereby reducing the need for complex control logic in the storage device while still achieving effective prefetching.
3Productivity
If host-accessible prefetcher queue is used, then prefetching efficiency is improved, but memory resource consumption increases
Solution Approach 1:
The prefetcher queue is implemented with local quality by allocating specific memory resources for the queue structure itself, rather than requiring large amounts of additional memory for data storage. The queue only stores metadata (addresses, control information) about prefetch requests, not the actual data, thus maintaining high prefetching efficiency while consuming minimal additional memory resources.
Solution Approach 2:
The system optimizes memory resource consumption by changing the parameters of the prefetcher queue implementation. Instead of using a large, fixed-size queue, the system uses dynamic queue management where the queue size and memory allocation are adjusted based on actual prefetching needs and available memory resources, thereby improving prefetching efficiency without excessive memory consumption.
Data Source
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AI summary
Systems and methods for prefetching data are disclosed. A processor executes a first command for moving first data stored in a storage device. Based on the first command, the processor stores, into a first queue of the storage device, a first address associated with the first data. The storage device further retrieves the first address from the first queue, retrieves the first data from the first storage medium based on the first address, and stores the first data to the second storage medium. In some embodiments, a process for prefetch optimization is also disclosed. A processor identifies a value for prefetching data. The processor runs an application, measures performance of the application, modifies the value based on the performance, and determines that the performance satisfies a criterion.