Cache Miss Detection Using Indication Logic
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Solution Overview
Problem
Current data processing systems face significant latency and power consumption issues due to cache misses, as existing techniques for early cache miss detection are not efficient enough to effectively abort cache accesses and manage resource allocation in multi-threaded environments.
Innovation Solution
The implementation of indication logic that provides a guaranteed safe indication of a cache miss before the lookup procedure is complete, using techniques like Bloom filters, to control processes affecting other program threads, thereby aborting unnecessary cache lookups and optimizing resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional cache lookup procedures are used to determine cache hits or misses, then accurate cache status detection is achieved, but significant latency and power consumption occur due to the complete lookup procedure
Solution Approach 1:
The patent applies preliminary action by performing a preliminary filter check using indication logic (such as Bloom filters or hash tables) before executing the complete cache lookup procedure. This early indication determines whether a cache miss is guaranteed, allowing the system to skip the full lookup procedure for certain cases, thereby reducing cache access latency while maintaining detection accuracy for guaranteed misses.
2Measurement precision
If traditional cache lookup procedures are used to determine cache hits or misses, then accurate cache status detection is achieved, but excessive power consumption occurs
Solution Approach 1:
The patent applies preliminary action by performing a preliminary filter check using indication logic (such as Bloom filters or hash tables) before executing the complete cache lookup procedure. This early indication determines whether a cache miss is guaranteed, allowing the system to skip the full lookup procedure for certain cases, thereby reducing cache access power consumption while maintaining detection accuracy for guaranteed misses.
3Loss of time
If early cache miss detection is implemented using indication logic, then cache access latency is reduced by aborting unnecessary lookups, but false indications may occur reducing reliability
Solution Approach 1:
The patent introduces an intermediary indication logic layer (such as Bloom filters or hash tables) that provides preliminary cache miss detection. This intermediary structure offers a probabilistic indication of cache misses with guaranteed correctness for negative indications, allowing the system to balance between reduced latency and maintained reliability by using the indication as a filter before complete lookup.
4Productivity
If multi-threaded processing is implemented to improve system throughput, then productivity is improved, but cache contention increases reducing overall efficiency
Solution Approach 1:
The patent applies preliminary action in multi-threaded environments by using indication logic to pre-assess cache miss probability for multiple threads before they access the cache. This allows the system to manage cache contention more effectively by identifying and aborting unnecessary cache lookups from multiple threads, thereby maintaining high productivity while reducing cache contention overhead.
Data Source
AI summary
A data processing apparatus and method are provided for detecting cache misses. The data processing apparatus has processing logic for executing a plurality of program threads, and a cache for storing data values for access by the processing logic. When access to a data value is required while executing a first program thread, the processing logic issues an access request specifying an address in memory associated with that data value, and the cache is responsive to the address to perform a lookup procedure to determine whether the data value is stored in the cache. Indication logic is provided which in response to an address portion of the address provides an indication as to whether the data value is stored in the cache, this indication being produced before a result of the lookup procedure is available, and the indication logic only issuing an indication that the data value is not stored in the cache if that indication is guaranteed to be correct. Control logic is then provided which, if the indication indicates that the data value is not stored in the cache, uses that indication to control a process having an effect on a program thread other than the first program thread.