PR: N-way Cache for unsafe_acquire!
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- Add CACHE_WAYS=4 constant for N-way set associative cache - Remove nd_views field (ReshapedArray needs no caching) - Add nd_next_way field for round-robin replacement counter - Implement linear search + round-robin replacement in get_nd_array! - Update empty! to handle new cache structure N-way cache prevents thrashing when alternating between different array dimensions in the same slot. Each slot can cache up to 4 different dimension patterns, returning cached Array instances instead of calling unsafe_wrap (which allocates 112 bytes).
- Add test_nway_cache.jl with thrashing prevention tests - Verify type checks (ReshapedArray vs Array returns) - Test cache invalidation on vector resize - Confirm CACHE_WAYS constant is accessible - Include new test file in runtests.jl
- Replace constant CACHE_WAYS with Preferences-based configuration - Add set_cache_ways!(n) function for runtime configuration - Support range 1-16 with validation and helpful error messages - Export CACHE_WAYS and set_cache_ways! from module - Add comprehensive tests for validation logic Users can now configure N-way cache size via: 1. AdaptiveArrayPools.set_cache_ways!(n) (requires restart) 2. LocalPreferences.toml: [AdaptiveArrayPools] cache_ways = n
- Add 4-way alternating zero-allocation test - Add 5-way acquire! test (ReshapedArray always 0 alloc) - Add 5-way unsafe_acquire! test (cache eviction causes alloc) - Add multiple slots with N-way cache test - Reorganize into 'N-way Cache' and 'N-way Zero-Allocation' testsets
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## master #5 +/- ##
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+ Coverage 97.16% 97.27% +0.10%
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Files 6 6
Lines 424 440 +16
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+ Hits 412 428 +16
Misses 12 12 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Pull request overview
This PR implements an N-way set associative cache for unsafe_acquire! to eliminate allocation thrashing when alternating between different array dimension patterns. The implementation adds a configurable cache (default 4 ways) that allows each pool slot to cache multiple dimension patterns using round-robin eviction.
Key Changes
- N-way set associative cache with configurable ways (default: 4) prevents cache thrashing when alternating between dimension patterns
- Preferences.jl integration for runtime configuration with validation (valid range: 1-16)
- Comprehensive test suite demonstrating zero-allocation behavior for patterns within cache capacity
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| src/types.jl | Adds CACHE_WAYS configuration with Preferences.jl, updates TypedPool structure with N-way cache fields (nd_arrays, nd_dims, nd_ptrs, nd_next_way), removes obsolete nd_views field |
| src/core.jl | Implements N-way cache logic in get_nd_array! with linear search for cache hits and round-robin replacement for misses, updates empty! to clear new cache fields |
| src/AdaptiveArrayPools.jl | Exports CACHE_WAYS constant and set_cache_ways! function for public API |
| test/test_nway_cache.jl | Adds comprehensive tests for N-way cache functionality, configuration validation, allocation behavior, cache invalidation, and multi-slot scenarios |
| test/runtests.jl | Includes new test file in test suite |
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Summary
Implement N-way set associative cache for
unsafe_acquire!to prevent thrashing when alternating between different dimension patterns.Changes
Core Implementation
CACHE_WAYSdimension patterns (default: 4)Performance
API Comparison
acquire!ReshapedArrayunsafe_acquire!ArrayConfiguration (Preferences.jl)
Option 1: Programmatic
Option 2: LocalPreferences.toml