Per-Selector Dispatch Cache for Method Call Optimization
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Solution Overview
Problem
Conventional method call operations in dynamically-typed and statically-typed object-oriented languages face inefficiencies due to slow runtime searches for target functions, leading to high memory consumption and discarded information in global caches, especially in polymorphic call sites.
Innovation Solution
Implementing a per-selector dispatch cache system that maps call sites to dispatch caches based on method selectors, using a global cache with per-selector caches indexed by selector identification, allowing for hash lookups to quickly determine if a target function exists, and dynamically adjusting cache sizes based on polymorphism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a global cache is used to store target functions for dynamic dispatch, then method call operations can be performed, but memory consumption increases and lookup speed decreases
Solution Approach 1:
The global cache is segmented into multiple per-selector caches, each dedicated to a specific method selector. This segmentation allows the system to store only relevant target functions for each selector rather than maintaining a single large global cache, reducing overall memory consumption while enabling faster targeted lookups.
Solution Approach 2:
The patent introduces a new dimension of organization by indexing caches based on method selectors rather than using a flat global structure. This selector-based indexing creates a hierarchical dimension that improves lookup efficiency by directly routing to the appropriate cache partition.
2Reliability
If runtime searches are performed in receiver class and super-classes for target functions, then correct method dispatch is achieved, but operation speed becomes too slow for optimized language implementation
Solution Approach 1:
The system performs preliminary actions by pre-computing and storing target function mappings in per-selector caches during compilation or initialization. This eliminates the need for runtime searches through class hierarchies, as the correct target function is already identified and cached based on the method selector and receiver class combination.
Solution Approach 2:
The per-selector cache acts as an intermediary between the method selector and the target function. Instead of directly searching through class hierarchies at runtime, the system uses the cache as a mediator that quickly resolves the selector to the appropriate target function, maintaining correctness while dramatically improving speed.
3Speed
If per-selector caches are implemented with hash lookups, then lookup speed increases, but cache management complexity increases
Solution Approach 1:
The hash lookup mechanism provides self-service by automatically computing hash values from method selectors and directly mapping them to the appropriate cache entries. This automated hashing eliminates the need for complex manual cache management or hierarchical search algorithms, achieving fast lookups while keeping management simple through the natural properties of hash functions.
Data Source
AI summary
Aspects of the subject technology relate to a computer-implemented process, including steps for compiling a first method call at a first call site in code of an object-oriented language, wherein the first call site is associated with a first selector, referencing a global cache comprising a plurality of per-selector caches, wherein each of the per-selector caches is indexed based on a corresponding selector identification and identifying a first per-selector cache, from among the plurality of per-selector caches, using the first selector. In certain aspects, the process can further include steps for invoking a method on a first object by performing a lookup in the first per-selector cache using a class associated with the first object to determine if a first target function exists in the first per-selector cache. Systems and computer readable media are also provided.