{
  "benchmark": "ldbc_t126_isolated_ab",
  "run_date": "2026-05-11T03:25Z",
  "hw_envelope": {
    "target": "AMD Ryzen 7950X (Zen 4, 16-core), 64 MB L3 (32 MB per CCD), 2-channel DDR5",
    "numa_nodes": 1
  },
  "experiment_design": {
    "variant_a": "commit a71f9e82 = T1.36 merge HEAD (pre-T1.26; 64-byte Person layout)",
    "variant_b": "current main = post-T1.26 + post-T1.43 + post-T1.45 + post-T1.46 + post-T1.47 (32-byte Person layout)",
    "endpoint": "/bench?queries=1000000 (single-thread IS-1)",
    "harness": "curl over HTTP — same path for both variants (apples-to-apples)",
    "scale": "SF1 (1M persons, 5M friendships, 5M messages)"
  },
  "results": {
    "pre_t126_a71f9e82": {
      "qps": 428042,
      "avg_us_per_lookup": 2.34,
      "p50_ns": 2100,
      "p99_ns": 5300,
      "elapsed_sec": 2.336,
      "person_entry_bytes": 64,
      "working_set_mb": 60
    },
    "post_t126_current_main": {
      "qps_run1": 543525,
      "qps_run2": 543567,
      "qps_run3": 555288,
      "qps_best_of_3": 555288,
      "qps_median_of_3": 543567,
      "avg_us_per_lookup_best": 1.8,
      "avg_us_per_lookup_median": 1.84,
      "p50_ns_best": 1700,
      "p99_ns_best": 4000,
      "elapsed_sec_best": 1.801,
      "person_entry_bytes": 32,
      "working_set_mb": 30
    },
    "t126_isolated_effect": {
      "qps_ratio_post_over_pre": 1.3,
      "avg_us_delta_post_minus_pre": -0.54,
      "p50_delta_ns": -400,
      "p99_delta_ns": -1300,
      "interpretation": "T1.26 bit-pack delivers +30% single-thread on Zen 4 7950X. NOT the 9.4x predicted by L-33."
    }
  },
  "disclaimer_warm_cache": "Warm-cache: both servers ran /load then /bench in immediate succession. No drop_caches between.",
  "disclaimer_single_run_pre_t126": "Pre-T1.26 measured single-run, not best-of-3. Likely close to true; re-measure if delta crosses falsification threshold.",
  "disclaimer_local_zen4_not_aws": "Zen 4 7950X != c6a.8xlarge Ice Lake. Hardware-specific cache + memory topology. L-33 prediction may still hold on AWS.",
  "publication_note": "Historical report extract. Preserve reported rates; article compares median 543567 with single earlier 428042. Report explanations and hardware labels are historical, not independent validation."
}