Hardware Accelerator Cache Consistency via Selective Write-Back
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In general-purpose computing systems with hardware accelerators, data inconsistency between the cache and main memory occurs due to write-back policies, leading to performance degradation and bottlenecks when using conventional solutions like flushing the cache or bypassing the cache, which can result in slow processing speeds and memory bottlenecks.
Innovation Solution
A device and method that determine whether an address accessed by the hardware accelerator is in the cache, and selectively perform write-back or invalidation processes based on the properties of the address, such as reference, overwrite, or complex processes, to maintain data consistency between the hardware accelerator and the host system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cache is flushed before activating the accelerator, then data consistency between cache and main memory is maintained, but processing speed becomes very slow and bottlenecks occur in system bus and memory
Solution Approach 1:
The patent applies preliminary action by determining whether cache data needs to be written back to main memory before the hardware accelerator is activated. The determination unit checks if the accelerator-accessed address is present in the cache, and if so, the control unit performs write-back operation in advance. This ensures data consistency is established before accelerator operation begins, preventing the need for complete cache flushing while maintaining reliability.
2Reliability
If the cache is bypassed by setting memory area to non-cacheable area, then data inconsistency problem is circumvented, but memory bottlenecks and performance degradation occur due to data movement requirements
Solution Approach 1:
The patent applies local quality by treating different cache addresses differently based on whether they are accessed by the hardware accelerator. The determination unit identifies accelerator-accessed addresses, and the control unit selectively performs write-back operations only for those specific addresses. This localized approach maintains data consistency for accelerator-accessed data while allowing other cache data to remain, avoiding the performance penalty of complete cache bypassing.
3Productivity
If the cache is used with write-back policy, then processing performance is improved, but data inconsistency occurs between cache and main memory when accelerator accesses memory
Solution Approach 1:
The patent applies feedback by implementing a determination unit that monitors and determines whether addresses accessed by the hardware accelerator are present in the cache. Based on this feedback information, the control unit selectively performs write-back operations. This feedback mechanism allows the system to maintain write-back cache performance while ensuring data consistency by writing back only the specific cache lines that the accelerator will access, rather than flushing the entire cache.
Data Source
AI summary
Disclosed is a device for maintaining consistency between a host system cache and a main memory in a general-purpose computing system equipped with a hardware accelerator for processing main memory data. The device for maintaining data consistency between a hardware accelerator and a host system, which is at least temporarily implemented by a computer, includes a determination unit responsible for determining whether an address which the hardware accelerator should access is present in a cache, and a processing unit responsible for selectively performing write-back on data corresponding to the address when the address is present in the cache based on the determined result.