73 lines
2.6 KiB
C
73 lines
2.6 KiB
C
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// hak_kpi_util.inc.h — KPI measurement helpers (Linux / non-Linux)
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#ifndef HAK_KPI_UTIL_INC_H
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#define HAK_KPI_UTIL_INC_H
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#ifdef __linux__
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// Latency histogram (simple buckets for P50/P95/P99)
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#define LATENCY_BUCKETS 100
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static uint64_t g_latency_histogram[LATENCY_BUCKETS];
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static uint64_t g_latency_samples = 0;
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// Baseline page faults (at init)
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static uint64_t g_baseline_soft_pf = 0;
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static uint64_t g_baseline_hard_pf = 0;
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static uint64_t g_baseline_rss_kb = 0;
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// Get page faults from /proc/self/stat
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static void get_page_faults(uint64_t* soft_pf, uint64_t* hard_pf) {
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FILE* f = fopen("/proc/self/stat", "r");
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if (!f) { *soft_pf = 0; *hard_pf = 0; return; }
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unsigned long minflt = 0, majflt = 0;
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unsigned long dummy; char comm[256], state;
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(void)fscanf(f, "%lu %s %c %lu %lu %lu %lu %lu %lu %lu %lu %lu",
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&dummy, comm, &state, &dummy, &dummy, &dummy, &dummy, &dummy,
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&dummy, &minflt, &dummy, &majflt);
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fclose(f);
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*soft_pf = minflt; *hard_pf = majflt;
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}
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// Get RSS from /proc/self/statm (in KB)
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static uint64_t get_rss_kb(void) {
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FILE* f = fopen("/proc/self/statm", "r");
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if (!f) return 0;
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unsigned long size, resident; (void)fscanf(f, "%lu %lu", &size, &resident); fclose(f);
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long page_size = sysconf(_SC_PAGESIZE);
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return (resident * page_size) / 1024; // Convert to KB
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}
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static uint64_t calculate_percentile(double percentile) {
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if (g_latency_samples == 0) return 0;
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uint64_t target = (uint64_t)(g_latency_samples * percentile);
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uint64_t cumulative = 0;
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for (size_t i = 0; i < LATENCY_BUCKETS; i++) {
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cumulative += g_latency_histogram[i];
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if (cumulative >= target) return i * 10; // Return bucket midpoint (ns)
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}
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return (LATENCY_BUCKETS - 1) * 10;
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}
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// Implement hak_get_kpi()
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void hak_get_kpi(hak_kpi_t* out) {
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memset(out, 0, sizeof(hak_kpi_t));
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// Latency (from histogram)
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out->p50_alloc_ns = calculate_percentile(0.50);
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out->p95_alloc_ns = calculate_percentile(0.95);
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out->p99_alloc_ns = calculate_percentile(0.99);
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// Page Faults (delta from baseline)
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uint64_t soft_pf, hard_pf; get_page_faults(&soft_pf, &hard_pf);
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out->soft_page_faults = soft_pf - g_baseline_soft_pf;
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out->hard_page_faults = hard_pf - g_baseline_hard_pf;
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// RSS (delta from baseline, in MB)
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uint64_t rss_kb = get_rss_kb();
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int64_t rss_delta_kb = (int64_t)rss_kb - (int64_t)g_baseline_rss_kb;
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out->rss_delta_mb = rss_delta_kb / 1024;
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}
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#else
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// Non-Linux: stub implementation
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void hak_get_kpi(hak_kpi_t* out) { memset(out, 0, sizeof(hak_kpi_t)); }
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#endif
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#endif // HAK_KPI_UTIL_INC_H
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