88717a8737
Target: Consolidate 3 ENV gate TLS reads → 1 TLS read - tiny_c7_ultra_enabled_env(): 1.28% self - tiny_front_v3_enabled(): 1.01% self - tiny_metadata_cache_enabled(): 0.97% self - Total overhead: 3.26% self (perf profile analysis) Implementation: - core/box/hakmem_env_snapshot_box.h (new): ENV snapshot struct & API - core/box/hakmem_env_snapshot_box.c (new): TLS snapshot implementation - core/front/malloc_tiny_fast.h: Migrated 5 call sites to snapshot - core/box/tiny_legacy_fallback_box.h: Migrated 2 call sites - core/box/tiny_metadata_cache_hot_box.h: Migrated 1 call site - core/bench_profile.h: Added hakmem_env_snapshot_refresh_from_env() - Makefile: Added hakmem_env_snapshot_box.o to build - ENV gate: HAKMEM_ENV_SNAPSHOT=0/1 (default: 0, research box) A/B Test Results (Mixed, 10-run, 20M iters): - Baseline (E1=0): 43,617,549 ops/s (avg), 43,562,895 ops/s (median) - Optimized (E1=1): 45,327,239 ops/s (avg), 45,309,218 ops/s (median) - Improvement: avg +3.92%, median +4.01% Decision: GO (+3.92% >= +2.5% threshold) - Action: Keep as research box (default OFF) for Phase 4 - Next: Consider promotion to default in MIXED_TINYV3_C7_SAFE preset Design Rationale: - Shape optimizations (B3, D3) reached saturation (+0.56% NEUTRAL) - Shift to memory/TLS overhead optimization (new optimization frontier) - Pattern: Similar to existing tiny_front_v3_snapshot (proven approach) - Expected: +1-3% from 3.26% ENV overhead → Achieved: +3.92% Technical Details: - Consolidation: 3 TLS reads → 1 TLS read (66% reduction) - Learner interlock: tiny_metadata_cache_eff pre-computed in snapshot - Version sync: Refreshes on small_policy_v7_version_changed() - Fallback safety: Existing ENV gates still available when E1=0 🤖 Generated with Claude Code Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
65 lines
2.3 KiB
C
65 lines
2.3 KiB
C
// hakmem_env_snapshot_box.h - Phase 4 E1: ENV Snapshot Consolidation
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//
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// Purpose: Consolidate 3 hot ENV gate calls into 1 TLS snapshot read
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// Target: tiny_c7_ultra_enabled_env (1.28%) + tiny_front_v3_enabled (1.01%) +
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// tiny_metadata_cache_enabled (0.97%) = 3.26% combined ENV overhead
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//
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// Design:
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// - ENV: HAKMEM_ENV_SNAPSHOT=0/1 (default 0, research box)
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// - Single TLS snapshot struct containing all hot toggles
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// - Lazy init with version-based refresh (follows tiny_front_v3_snapshot pattern)
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// - Learner interlock: tiny_metadata_cache_eff = cache && !learner
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//
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// Benefits:
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// - 3 TLS reads → 1 TLS read (66% reduction)
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// - 3 lazy init checks → 1 lazy init check
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// - Expected gain: +1-3% (conservative from 3.26% overhead)
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#ifndef HAK_ENV_SNAPSHOT_BOX_H
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#define HAK_ENV_SNAPSHOT_BOX_H
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#include <stdbool.h>
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#include <stdlib.h>
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// ENV snapshot struct: consolidates all hot ENV gates
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typedef struct HakmemEnvSnapshot {
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bool tiny_c7_ultra_enabled; // ENV: HAKMEM_TINY_C7_ULTRA (default 1)
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bool tiny_front_v3_enabled; // ENV: HAKMEM_TINY_FRONT_V3_ENABLED (default 1)
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bool tiny_metadata_cache; // ENV: HAKMEM_TINY_METADATA_CACHE (default 0)
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bool tiny_metadata_cache_eff; // Effective: cache && !learner (for hot path)
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} HakmemEnvSnapshot;
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// Global snapshot state (implemented in hakmem_env_snapshot_box.c)
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extern HakmemEnvSnapshot g_hakmem_env_snapshot;
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extern int g_hakmem_env_snapshot_ready;
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// Snapshot initializer (implemented in hakmem_env_snapshot_box.c)
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void hakmem_env_snapshot_init(void);
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// Refresh from ENV (for bench_profile putenv sync)
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void hakmem_env_snapshot_refresh_from_env(void);
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// Fast snapshot getter: lazy init + 1 TLS read
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static inline const HakmemEnvSnapshot* hakmem_env_snapshot(void) {
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if (__builtin_expect(!g_hakmem_env_snapshot_ready, 0)) {
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hakmem_env_snapshot_init();
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}
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return &g_hakmem_env_snapshot;
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}
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// ENV gate: default OFF (research box, set =1 to enable)
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static inline bool hakmem_env_snapshot_enabled(void) {
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static int g = -1;
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if (__builtin_expect(g == -1, 0)) {
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const char* e = getenv("HAKMEM_ENV_SNAPSHOT");
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if (e && *e) {
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g = (*e == '1') ? 1 : 0;
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} else {
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g = 0; // default: OFF (research box)
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}
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}
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return g != 0;
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}
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#endif // HAK_ENV_SNAPSHOT_BOX_H
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