d54893ea1d
Step 2 & 3 Complete: - A/B test (Mixed 10-run): STATIC_ROUTE=0 (38.91M) → =1 (39.77M) = +2.20% avg - Median gain: +1.98% - Result: ✅ GO (exceeds +1.0% threshold) - Decision: ✅ ADOPT into MIXED_TINYV3_C7_SAFE preset - bench_profile.h line 77: HAKMEM_TINY_STATIC_ROUTE=1 default - Learner auto-disables static route when HAKMEM_SMALL_LEARNER_V7_ENABLED=1 Implementation Summary: - core/box/tiny_static_route_box.{h,c}: Research box (Step 1A) - core/front/malloc_tiny_fast.h: Route lookup integration (Step 1B, lines 249-256) - core/bench_profile.h: Bench sync + preset adoption Cumulative Phase 2-3 Gains: - B3 (Routing shape): +2.89% - B4 (Wrapper split): +1.47% - C3 (Static routing): +2.20% - Total: ~6.8% (35.2M → ~39.8M ops/s) Next: Phase 3 C1 (TLS Prefetch, expected +2-4%) 🤖 Generated with Claude Code Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/**
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* @file tiny_layout_box.h
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* @brief Box: Tiny Allocator Layout Definitions
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*
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* MISSION: Single source of truth for class size and header layout
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*
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* Current Design (Phase E1-CORRECT):
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* - All classes (0-7) have 1-byte header
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* - User pointer = base + 1 for ALL classes (0-7)
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* - Freed blocks store next pointers intrusively:
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* - C0/C7: next at base+0 (header overwritten while free)
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* - C1-C6: next at base+1 (header preserved while free)
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* - No external code should hardcode offsets; use this box API
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*/
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#ifndef TINY_LAYOUT_BOX_H
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#define TINY_LAYOUT_BOX_H
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#include <stddef.h>
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#include "../hakmem_tiny_config.h" // For g_tiny_class_sizes and TINY_NUM_CLASSES
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// A/B Toggle: Headerless mode
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// ENV: HAKMEM_TINY_HEADERLESS=1 to enable
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// Default: 0 (Phase 1 compatible)
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#ifndef HAKMEM_TINY_HEADERLESS
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#define HAKMEM_TINY_HEADERLESS 0
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#endif
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#include "../hakmem_build_flags.h"
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// Define all class-specific layout parameters
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// Current: Defined in g_tiny_class_sizes[8] in hakmem_tiny.c
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// This file makes them accessible via a unified Box API
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// Header size
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static inline size_t tiny_header_size(int class_idx) {
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#if HAKMEM_TINY_HEADERLESS
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(void)class_idx;
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return 0;
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#elif HAKMEM_TINY_HEADER_CLASSIDX
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(void)class_idx;
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return 1;
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#else
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(void)class_idx;
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return 0;
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#endif
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}
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// Legacy macro for backward compatibility (Phase 1)
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#define TINY_HEADER_SIZE 1
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// Validation macros
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static inline int tiny_class_is_valid(int class_idx) {
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return class_idx >= 0 && class_idx < TINY_NUM_CLASSES;
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}
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static inline size_t tiny_class_stride(int class_idx) {
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// Use the extern global definition from hakmem_tiny_config.h
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// g_tiny_class_sizes is defined in core/hakmem_tiny_config_box.inc
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return tiny_class_is_valid(class_idx) ? g_tiny_class_sizes[class_idx] : 0;
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}
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// Calculate user pointer offset from base pointer
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// This logic centralizes the "User = Base + 1" vs "User = Base + 0" decision
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static inline size_t tiny_user_offset(int class_idx) {
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#if HAKMEM_TINY_HEADERLESS
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(void)class_idx;
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return 0; // Headerless: user = base
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#elif HAKMEM_TINY_HEADER_CLASSIDX
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(void)class_idx;
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// Phase E1-CORRECT: All classes have 1-byte header → user = base + 1
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return 1u;
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#else
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(void)class_idx;
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return 0u;
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#endif
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}
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// Offset for storing the freelist next pointer inside a freed block.
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// This is distinct from tiny_user_offset():
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// - User offset is always +1 in header mode.
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// - Next offset is 0 for C0/C7 (cannot preserve header while free), else 1.
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static inline size_t tiny_nextptr_offset(int class_idx) {
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#if HAKMEM_TINY_HEADERLESS
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(void)class_idx;
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return 0;
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#elif HAKMEM_TINY_HEADER_CLASSIDX
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// Bit pattern: C0=0, C1-C6=1, C7=0 → 0b01111110 = 0x7E
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return (0x7Eu >> ((unsigned)class_idx & 7u)) & 1u;
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#else
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(void)class_idx;
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return 0u;
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#endif
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}
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#endif // TINY_LAYOUT_BOX_H
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