74 lines
2.7 KiB
C
74 lines
2.7 KiB
C
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// tiny_c2_local_cache.h - Phase 79-1: C2 Local Cache Fast-Path API
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//
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// Goal: Zero-overhead always-inline push/pop for C2 FIFO ring buffer
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// Scope: C2 allocations (32-64B)
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// Design: Fail-fast to unified_cache on full/empty
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//
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// Fast-Path Strategy:
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// - Always-inline push/pop for zero-call-overhead
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// - Modulo arithmetic inlined (tail/head)
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// - Return NULL on empty, 0 on full (caller handles fallback)
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// - No bounds checking (ring size fixed at compile time)
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//
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// Integration Points:
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// - Alloc: Call c2_local_cache_pop() in tiny_front_hot_box BEFORE unified_cache
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// - Free: Call c2_local_cache_push() in tiny_legacy_fallback BEFORE unified_cache
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//
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// Rationale:
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// - Same pattern as C3/C4/C5/C6 inline slots (proven +7.05% C4-C6 cumulative)
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// - Phase 79-0 analysis: C2 Stage3 backend lock contention (not well-served by TLS)
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// - Lightweight cap (64) = 512B/thread (Phase 79-0 specification)
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// - Fail-fast design = no performance cliff if full/empty
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#ifndef HAK_FRONT_TINY_C2_LOCAL_CACHE_H
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#define HAK_FRONT_TINY_C2_LOCAL_CACHE_H
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#include <stdint.h>
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#include "../box/tiny_c2_local_cache_tls_box.h"
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#include "../box/tiny_c2_local_cache_env_box.h"
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// ============================================================================
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// C2 Local Cache: Fast-Path Push/Pop (Always-Inline)
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// ============================================================================
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// Get TLS pointer for C2 local cache
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// Inline for zero overhead
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static inline TinyC2LocalCache* c2_local_cache_tls(void) {
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extern __thread TinyC2LocalCache g_tiny_c2_local_cache;
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return &g_tiny_c2_local_cache;
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}
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// Push pointer to C2 local cache ring
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// Returns: 1 if success, 0 if full (caller must fallback to unified_cache)
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__attribute__((always_inline))
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static inline int c2_local_cache_push(TinyC2LocalCache* cache, void* ptr) {
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// Check if ring is full
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if (__builtin_expect(c2_local_cache_full(cache), 0)) {
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return 0; // Full, caller must use unified_cache
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}
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// Enqueue at tail
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cache->slots[cache->tail] = ptr;
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cache->tail = (cache->tail + 1) % TINY_C2_LOCAL_CACHE_CAPACITY;
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return 1; // Success
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}
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// Pop pointer from C2 local cache ring
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// Returns: non-NULL if success, NULL if empty (caller must fallback to unified_cache)
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__attribute__((always_inline))
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static inline void* c2_local_cache_pop(TinyC2LocalCache* cache) {
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// Check if ring is empty
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if (__builtin_expect(c2_local_cache_empty(cache), 0)) {
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return NULL; // Empty, caller must use unified_cache
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}
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// Dequeue from head
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void* ptr = cache->slots[cache->head];
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cache->head = (cache->head + 1) % TINY_C2_LOCAL_CACHE_CAPACITY;
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return ptr; // Success
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}
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#endif // HAK_FRONT_TINY_C2_LOCAL_CACHE_H
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