Texture Cache Slot Selection for Graphics Memory Latency

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Solution Overview

Problem

Graphics processing systems face inefficiencies in cache resource allocation due to varying texture data formats and sizes, leading to memory latency and reduced performance, as existing cache systems lack an optimized method for selecting and managing cache slots and sets effectively.

Innovation Solution

A data-dependent slot selection scheme is implemented, where texture attributes are analyzed to determine specific cache slot and set address data fields, optimizing cache allocation based on the size and configuration of the data to prevent overwriting and ensure efficient use of cache resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If a graphics cache is used to store texture data, then data access time is reduced and memory latency is decreased, but the cache capacity is insufficient to store the entire texture map

Engineering Contradiction:
Improvedata access timeVSAvoidcache capacity
Core Design Contradiction:
Loss of timeVSQuantity of substance

Solution Approach 1:

The texture map is divided into multiple cache lines, and each cache line is further divided into multiple slots. This segmentation allows the limited cache capacity to store more texture data by organizing it into manageable units that can be selectively loaded and stored in the cache hierarchy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a two-level cache system with L1 and L2 caches, adding a dimensional layer to the cache structure. The L2 cache provides additional storage capacity while the L1 cache maintains fast access for frequently used data, effectively increasing overall cache capacity without sacrificing access speed for critical data.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the cache size is increased to store more texture data, then data availability is improved, but cache access time increases and performance degrades

Engineering Contradiction:
Improvecache sizeVSAvoidcache access time
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

By segmenting the cache into multiple slots within each cache line, the system can selectively access only the specific slot containing the required data. This reduces the effective access time compared to searching through a monolithic large cache, as the slot selection logic quickly identifies and retrieves the needed data portion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts only the necessary texture data into the L1 cache based on prediction algorithms, while storing less frequently accessed data in the L2 cache. This extraction strategy ensures that the L1 cache contains only the most relevant data for current processing, maintaining fast access times while still providing large overall capacity through the L2 cache.

Inventive Principle:
Principle #2Taking out (Extraction)

3Quantity of substance

If a two-level cache system is implemented to increase cache size, then data availability and decreased memory access time are achieved, but issues arise regarding selection and transfer of data to the cache system

Engineering Contradiction:
Improvecache sizeVSAvoiddata selection and transfer logic
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by predicting which texture data will be needed soon and pre-loading it into the appropriate cache levels before it is actually required. This prediction-based pre-loading reduces the complexity of data selection logic, as the system proactively prepares the cache rather than needing complex real-time decision-making about what to load.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cache system incorporates automatic management features where the cache controller autonomously handles data selection, transfer, and eviction based on predefined policies and hardware status flags. This self-service approach reduces the complexity of external control logic, as the cache system manages its own data organization and selection without requiring complex external intervention.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If logic for loading data into cache is not optimized for data size or configuration, then cache loading is simplified, but overwriting or trashing of valid data occurs resulting in inefficient use of cache resources

Engineering Contradiction:
Improvecache loading logicVSAvoiddata validity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The cache loading logic is made dynamic by using status flags and attributes associated with each cache line to determine loading behavior. The system adaptively adjusts which slots to load based on real-time cache state, data attributes, and prediction outcomes, ensuring that valid data is not overwritten while maintaining relatively simple loading logic through standardized flag-based control.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS7483035B2Texture cache control using a data dependent slot selection scheme
Publication Date: 2009.01.27 VIA TECH INC
  • US7483035B2 patent drawing
  • US7483035B2 patent drawing
  • US7483035B2 patent drawing

AI summary

Provided are methods, systems, and graphics processing apparatus, for improving graphics system performance using a data dependent slot and set selection technique for receiving texture data into an L2 cache for providing a high utilization of system resources in a diverse texture processing environment.