Coherent Agents For Memory Access

What is this patent about?

’445 is related to the field of data processing in multi-core systems, specifically addressing the challenge of maintaining data coherency when using hardware accelerators. Traditional multi-core systems rely on coherency protocols to ensure that all processing cores have a consistent view of shared data, preventing data corruption and ensuring correct operation. However, accelerators, which are specialized hardware components designed to accelerate specific workloads, often operate outside the coherency domain, leading to potential inconsistencies and performance bottlenecks.

The underlying idea behind ’445 is to introduce a coherent agent that acts as an intermediary between the coherency fabric and the application accelerator. This agent monitors the state of data within the coherency domain and provides this information to an application accelerator agent . The application accelerator agent then uses this information to ensure that the accelerator accesses data in a coherent manner, effectively extending the coherency domain to include the accelerator.

The claims of ’445 focus on a system comprising a coherency fabric, an accelerator agent, and a coherent agent. The coherent agent supports the coherency protocol and obtains state information about data usage by processing components. This state information is then provided to the accelerator agent, which can modify the performance of data operations based on the type of access and the state information, ensuring coherent data access for the application.

In practice, the coherent agent monitors the system fabric for snoop requests and other coherency-related traffic. It maintains a record of the cache state (e.g., clean, dirty, shared, exclusive) for each cache line that the accelerator is working on. When the application accelerator agent needs to access data, it consults the coherent agent to determine the appropriate access method (e.g., read shared, write exclusive). The coherent agent then ensures that the accelerator's access adheres to the coherency protocol, preventing data corruption and ensuring that the accelerator operates on the most up-to-date data.

This approach differs from prior solutions by providing a flexible and scalable way to integrate accelerators into a coherent memory system. Instead of requiring each accelerator to implement the full coherency protocol, ’445 uses a dedicated coherent agent to handle the complexities of coherency management. This allows accelerators to focus on their specific tasks while still benefiting from the guarantees of a coherent memory system. Furthermore, a single coherent agent can support multiple application accelerator agents, making the solution adaptable to various application requirements and hardware configurations.