/* hakmem_ace_metrics.h - ACE Learning Layer Metrics Collection
 *
 * メトリクス収集システム:
 *   - Fast metrics (1Hz): throughput, LLC miss, mutex wait, backlog
 *   - Slow metrics (60s): fragmentation ratio, RSS
 *   - Inline helpers for hot-path tracking
 */

#ifndef HAKMEM_ACE_METRICS_H
#define HAKMEM_ACE_METRICS_H

#include <stdint.h>
#include <stdbool.h>
#include <stdatomic.h>
#include <time.h>

/* メトリクス構造体 */
struct hkm_ace_metrics {
    /* Fast metrics (updated every 0.5-1s) */
    uint64_t throughput_ops;        /* Operations per second */
    double   llc_miss_rate;         /* LLC miss rate (0.0-1.0) */
    uint64_t mutex_wait_ns;         /* Cumulative mutex contention time */
    uint32_t remote_free_backlog[8]; /* Per-class remote free backlog */

    /* Slow metrics (updated every 60s) */
    double   fragmentation_ratio;   /* allocated / reserved bytes */
    uint64_t rss_mb;                /* Resident set size in MB */

    /* Timestamp */
    uint64_t timestamp_ms;          /* Collection timestamp */
};

/* グローバルカウンタ（hot-path用） */
extern _Atomic uint64_t g_ace_alloc_count;
extern _Atomic uint64_t g_ace_free_count;
extern _Atomic uint64_t g_ace_mutex_wait_ns;

/* 初期化・破棄 */
void hkm_ace_metrics_init(void);
void hkm_ace_metrics_destroy(void);

/* メトリクス収集 */
void hkm_ace_metrics_collect(struct hkm_ace_metrics *out);
void hkm_ace_metrics_collect_fast(struct hkm_ace_metrics *out);
void hkm_ace_metrics_collect_slow(struct hkm_ace_metrics *out);

/* Hot-path inline helpers */

/* アロケーションカウント（高速インクリメント） */
static inline void hkm_ace_track_alloc(void) {
    atomic_fetch_add_explicit(&g_ace_alloc_count, 1, memory_order_relaxed);
}

/* フリーカウント（高速インクリメント） */
static inline void hkm_ace_track_free(void) {
    atomic_fetch_add_explicit(&g_ace_free_count, 1, memory_order_relaxed);
}

/* ミューテックス待機時間トラッキング
 * 使い方:
 *   uint64_t t0 = hkm_ace_mutex_timer_start();
 *   pthread_mutex_lock(&lock);
 *   hkm_ace_mutex_timer_end(t0);
 */
static inline uint64_t hkm_ace_mutex_timer_start(void) {
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    return (uint64_t)ts.tv_sec * 1000000000ULL + (uint64_t)ts.tv_nsec;
}

static inline void hkm_ace_mutex_timer_end(uint64_t start_ns) {
    struct timespec ts;
    clock_gettime(CLOCK_MONOTONIC, &ts);
    uint64_t end_ns = (uint64_t)ts.tv_sec * 1000000000ULL + (uint64_t)ts.tv_nsec;
    uint64_t delta = (end_ns > start_ns) ? (end_ns - start_ns) : 0;
    atomic_fetch_add_explicit(&g_ace_mutex_wait_ns, delta, memory_order_relaxed);
}

/* LLC miss monitoring (rdpmc wrapper) */
bool hkm_ace_llc_available(void);
void hkm_ace_llc_read(uint64_t *misses, uint64_t *references);

#endif /* HAKMEM_ACE_METRICS_H */