Stack Distance Histogram for Cache Miss Rate Prediction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for predicting cache miss rates are either time-consuming and lack insight into the inherent properties of memory reference traces, or they fail to accurately estimate cold misses and are expensive due to large data requirements.
Innovation Solution
A mechanism and method using a stack distance histogram, stack filter fraction, and stack merge fraction to characterize temporal and spatial locality of memory reference traces, enabling an analytical cache model that predicts cache miss rates efficiently and accurately across various cache sizes and organizations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cache simulation is used to predict cache miss rates, then exact hit rates for a given cache organization can be obtained, but the process becomes very time consuming and can only be applied to a small set of possible cache organizations
Solution Approach 1:
The patent segments the memory reference trace into smaller units and uses sampling techniques to analyze only representative portions of the trace. By dividing the full trace into multiple segments and selecting samples from each, the system achieves accurate cache miss rate predictions without processing the entire trace, thus reducing time consumption while maintaining precision.
Solution Approach 2:
The patent creates simplified copies or models of the cache organization being analyzed. Instead of simulating the full complex cache system with all its details, the invention uses abstracted representations that capture the essential behavior needed for accurate miss rate prediction, significantly reducing simulation time while preserving measurement accuracy.
2Measurement precision
If long memory reference traces are used in cache simulation, then accurate cache hit rates can be obtained, but storage and communication costs become expensive and difficult
Solution Approach 1:
The patent extracts only the essential characteristics and parameters from long memory reference traces that are necessary for accurate cache performance prediction. By identifying and extracting key features such as access patterns, temporal locality, and spatial locality metrics, the system achieves accurate predictions without storing or processing the complete trace data, dramatically reducing storage requirements.
Solution Approach 2:
The patent transforms the raw memory reference trace data into a different parameter space by computing statistical measures and characteristics. Instead of storing individual memory addresses and timestamps, the system converts the trace into aggregated parameters such as stack distance histograms, reference interval distributions, and locality metrics, which occupy far less storage space while preserving the information needed for accurate cache simulation.
3Loss of information
If cache simulation is used to obtain miss rates, then insights into temporal and spatial locality can be gained, but only in a vague and qualitative manner
Solution Approach 1:
The patent replaces qualitative visual inspection and vague interpretation of simulation results with precise mathematical and statistical methods. By applying formal definitions of temporal locality (stack distance) and spatial locality (reference intervals) and computing them using rigorous statistical analysis, the system transforms subjective insights into objective, quantifiable measurements with high precision.
Data Source
AI summary
A method and apparatus for determining a stack distance histogram for running software. The method may include receiving a plurality of memory references each including a corresponding address. The method may also include performing a first hash function and a second hash function on each received address. In addition, the method may include selectively storing an indication representative of each corresponding address in a hash table dependent upon results of the first hash function and the second hash function. A stack distance may then be determined based upon contents of the hash table.


