Track Table Pre-fetching for Cache Miss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cache systems face bottlenecks in performance due to the widening gap between processor speed and memory speed, leading to increased cache misses, especially in multi-way set associative configurations, which limit cache capacity and efficiency.
Innovation Solution
The method involves pre-fetching instruction segments into a higher level memory using a track table system that extracts branch information, allowing for pre-fetching of branch target instructions before execution, thereby reducing cache misses and eliminating the need for traditional cache tag matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-way set associative cache is used to reduce conflict misses, then cache efficiency is improved, but the number of ways is limited due to power and speed limitations
Solution Approach 1:
The patent implements pre-fetching of instruction segments into the cache before they are actually needed by the processor. By analyzing branch information and predicting future instruction needs, the system proactively loads data into the cache, eliminating the need for complex multi-way set associative structures to handle all possible access patterns simultaneously.
2Speed
If cache capacity is increased to match processor speed, then performance is improved, but traditional cache structures require multiple layers with slower lower level caches
Solution Approach 1:
The system pre-fetches instruction segments into the cache based on branch prediction and track table analysis, ensuring that needed instructions are already in the fast cache before the processor needs them. This approach allows the cache to maintain smaller capacity while achieving high effective speed by having the right data ready in advance.
Solution Approach 2:
The cache system uses its own resources (track table, branch information extraction) to automatically determine and load its own future needs, eliminating the need for complex multi-layer cache hierarchies. The cache serves itself by predicting and pre-loading instructions, reducing dependency on slower lower-level caches.
3Measurement precision
If traditional cache tag matching is used, then cache hits are detected, but cache misses still occur due to the gap between processor and memory speed
Solution Approach 1:
The system performs pre-fetching of instruction segments based on branch prediction before cache misses occur. By analyzing branch information and creating tracks of instruction segments, the system loads predicted instructions into the cache in advance, eliminating the time penalty associated with cache misses while maintaining accurate tag matching for actual hits.
Data Source
AI summary
A method for assisting operations of a processor core coupled to a first memory and a second memory includes: examining instructions being filled from the first memory to the second memory to extract instruction information containing at least branch information of the instructions, and creating a plurality of tracks based on the extracted instruction information. Further, the method includes filling one or more instructions from the first memory to the second memory based on one or more tracks from the plurality of tracks before the processor core starts executing the instructions, such that the processor core fetches the instructions from the second memory for execution. Filling the instructions further includes pre-fetching from the first memory to the second memory instruction segments containing the instructions corresponding to at least two levels of branch target instructions based on the one or more tracks.