CXL Storage Controller Workload Placement via Cache Coherence
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Solution Overview
Problem
Existing storage devices face challenges in efficiently managing input/output workloads in environments with a large number of storage devices communicating with a host device, leading to suboptimal performance and resource utilization.
Innovation Solution
The implementation of a storage device based on the CXL interface, which includes a controller that constructs a data structure containing performance information and network routing information, and transmits it to the host device using a cache coherence protocol. The host device then determines the most suitable storage device for workload placement based on this information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple storage devices communicate with the host device using traditional interfaces, then the host device can manage various peripheral devices, but the input/output workload performance deteriorates due to the large number of storage devices
Solution Approach 1:
The patent segments the monolithic storage management approach into distributed storage devices, each with its own controller that independently manages workloads. Each storage device operates autonomously with its own cache memory and controller, dividing the overall storage management task across multiple independent units rather than relying on a centralized host device management approach.
Solution Approach 2:
The patent introduces a new dimension of storage management by implementing a cache coherence protocol that enables storage devices to directly communicate and coordinate with each other, bypassing the traditional host-mediated communication path. This creates a peer-to-peer communication dimension that reduces host device overhead and improves overall I/O performance.
2Adaptability or versatility
If the host device manages a large number of storage devices, then peripheral device capability increases, but resource utilization becomes suboptimal
Solution Approach 1:
The patent implements feedback mechanisms where storage device controllers monitor their own workload performance and cache status, then make autonomous decisions about workload distribution. The cache coherence protocol provides real-time feedback about cache validity and storage device availability, enabling dynamic resource allocation that optimizes energy utilization while maintaining high device management capability.
Solution Approach 2:
Storage device controllers autonomously manage their own workloads and coordinate with each other through the cache coherence protocol without requiring constant host device intervention. Each controller independently determines workload placement based on local cache status and performance metrics, enabling self-service operation that improves resource utilization efficiency.
3Productivity
If storage devices transmit performance information to the host device, then workload placement can be optimized, but communication overhead increases
Solution Approach 1:
Storage device controllers pre-establish cache coherence relationships and exchange performance information proactively before workload placement decisions are needed. The system performs preliminary cache validation and performance metric collection in advance, so that when workload placement is required, the information is already available locally, reducing communication delays.
Solution Approach 2:
The cache coherence protocol acts as an intermediary mechanism that efficiently mediates communication between storage device controllers and the host device. Rather than direct, frequent transmissions of performance information, the protocol provides a standardized, optimized communication path that reduces overhead while enabling necessary information exchange for workload placement optimization.
Data Source
AI summary
Disclosed is a method which is performed by a controller of a storage device including a nonvolatile memory. The method includes constructing, at the controller, a data structure including at least one of performance information of the storage device and network routing information about a network where the storage device is located, and transmitting, at the controller, the data structure to the host device based on a cache coherence protocol.