diff --git a/models/experimental/MODEL_TIMING.ja.md b/models/experimental/MODEL_TIMING.ja.md
new file mode 100644
index 0000000..c823e3d
--- /dev/null
+++ b/models/experimental/MODEL_TIMING.ja.md
@@ -0,0 +1,56 @@
+<!-- SPDX-License-Identifier: MIT -->
+# 単一モデルの native 処理時間
+
+`model_timing.py` はlegacy/identity/filteredの3モデルを同じharness・library・corpusで測定する。
+Pythonはbuild・入力選択・実行順制御だけを担当し、計時はC++の`steady_clock`で行う。
+全detector、Python API、複数候補競合、マルチスレッドのbenchmarkではない。
+
+```sh
+taskset -c 2 uv run --no-project python models/experimental/model_timing.py \
+  /disk/identity-training.json /disk/filtered-training.json /disk/validation/manifest.json \
+  build/release/src/libuchardet.a /disk/timing.json --iterations 20000 --repeats 7
+```
+
+CPU番号は実行環境のallowed affinityから選ぶ。Linuxの1 CPU固定を要求し、未固定なら拒否する。
+CPU名・governorの前後値、OS/kernel、compiler/flags、library/model/input/binaryのhashを保存する。
+governorやboostを変更しない。affinityはCPUの占有、SMT相方の停止、周波数一定を保証しない。
+測定中は別のbuild/test等の重い作業を実行しない。
+
+## 計測区間
+
+入力を一度読み、scratch bufferとproberを一度確保した後、次をC++内で繰り返す。
+
+1. prober reset
+2. 同じ全文入力を既存filterへ渡す
+3. 非空のfilter結果をproberへ一回feed
+4. 内部confidence取得・bit変換・volatile checksum更新
+
+入力I/O、process起動、Python、コンパイル、入力/scratch/proberの確保、JSON出力は区間外。
+128回のwarm-upも区間外。iteration数は1〜1,000,000、試行数は3〜31。
+各processは10秒timeout。時間不足なら勝手にiterationを減らしたreportを出さず失敗する。
+
+全モデルを先にbuildし、文書・試行ごとに3モデルの実行順を循環させる。
+計測前の非計測観測と、各試行の最終counter/state/confidence/reset結果が一致することを検証。
+checksumはconfidence bits × iteration数とも照合する。
+既存filter/prober処理・table・公開APIは変更しない。
+
+## 集計の意味
+
+各試行の`elapsed_ns / iterations`から文書別median/min/maxを計算する。
+`p95_trial_mean_ns_per_iteration`は試行平均のnearest-rank p95であり、
+**リクエスト単位のp95 latencyではない**。7試行なら最大の試行平均になる。
+
+`summed_document_trial_summary`は同じ試行番号の独立した文書別計時を合計したもの。
+各文書を同じ回数評価する比較用の値で、corpusを交互に巡回する処理を実測した値ではない。
+同じ文書を繰り返すためcacheが温まる。異なる文書が連続するingestion workloadへの
+一般化には別benchmarkが必要である。
+
+計時値は再実行で変動する。JSON全byteの一致を性能の再現性と扱わず、独立runの分布を比較する。
+保存先はrunごとに変える。異なる既存reportを上書きしない。
+
+## 採用判断とは別
+
+このtoolは単一モデルのreuse処理コストだけを測る。allocation数、ピークmemory、
+モデル生成時間、全detectorのthroughput/候補順位は未測定。
+新規モデルの品質・権利・confidence校正は別gateであり、速さだけで採用しない。
+CIの短い反復は計測機構と出力一致のtestで、性能数値を主張するものではない。
diff --git a/models/experimental/model_timing.py b/models/experimental/model_timing.py
new file mode 100644
index 0000000..caed9f4
--- /dev/null
+++ b/models/experimental/model_timing.py
@@ -0,0 +1,182 @@
+# SPDX-License-Identifier: MIT
+"""Pinned-CPU warmed native single-model timing; no Python or file I/O in measured interval."""
+
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import platform
+import statistics
+import tempfile
+from pathlib import Path
+
+import native_comparison
+import sequence_probe
+from model import canonical, digest, write_idempotent
+from sequence_contract import content_hash
+
+NAMES = ("legacy", "identity", "filtered")
+
+
+def summary(trials, iterations):
+    if not trials or any(type(value) is not int or value <= 0 for value in trials):
+        raise ValueError("positive integer trial times required")
+    if type(iterations) is not int or not 1 <= iterations <= 1000000:
+        raise ValueError("invalid iteration count")
+    values = sorted(value / iterations for value in trials)
+    return dict(
+        median_ns_per_iteration=statistics.median(values),
+        minimum_ns_per_iteration=values[0],
+        maximum_ns_per_iteration=values[-1],
+        # Nearest-rank p95 of trial averages, NOT per-request tail latency.
+        p95_trial_mean_ns_per_iteration=values[(95 * len(values) + 99) // 100 - 1],
+    )
+
+
+def affinity():
+    if not hasattr(os, "sched_getaffinity"):
+        raise ValueError("this benchmark runner requires Linux CPU affinity")
+    cpus = sorted(os.sched_getaffinity(0))
+    if len(cpus) != 1:
+        raise ValueError("pin the process to one allowed CPU with taskset")
+    return cpus
+
+
+def cpu_environment(cpu):
+    info = {}
+    for block in Path("/proc/cpuinfo").read_text(encoding="utf-8").split("\n\n"):
+        fields = dict(line.split(":", 1) for line in block.splitlines() if ":" in line)
+        fields = {key.strip(): value.strip() for key, value in fields.items()}
+        if fields.get("processor") == str(cpu):
+            info["model_name"] = fields.get("model name")
+            break
+    governor = Path(f"/sys/devices/system/cpu/cpu{cpu}/cpufreq/scaling_governor")
+    info["scaling_governor"] = governor.read_text().strip() if governor.is_file() else None
+    return info
+
+
+def run(
+    identity, filtered, manifest, root, split, library, iterations=20000, repeats=7, compiler="c++"
+):
+    if type(iterations) is not int or not 1 <= iterations <= 1000000:
+        raise ValueError("iterations must be in [1, 1000000]")
+    if type(repeats) is not int or not 3 <= repeats <= 31:
+        raise ValueError("repeats must be in [3, 31]")
+    cpus = affinity()
+    cpu_info = cpu_environment(cpus[0])
+    records = native_comparison.select_records(identity, filtered, manifest, root, split)
+    library = Path(library).resolve(strict=True)
+    library_hash = digest(library.read_bytes())
+    profiles, binaries, baselines = {}, {}, {}
+    with tempfile.TemporaryDirectory(prefix="uchardet-model-timing-") as temporary:
+        for name, training in (("legacy", None), ("identity", identity), ("filtered", filtered)):
+            directory = Path(temporary) / name
+            directory.mkdir()
+            binary, provenance = (
+                sequence_probe.build_reference(library, directory, compiler)
+                if training is None
+                else sequence_probe.build(training["contract"], library, directory, compiler)
+            )
+            if provenance["static_library_sha256"] != library_hash:
+                raise ValueError("library differs between model builds")
+            binaries[name] = binary
+            baselines[name] = {
+                source["id"]: sequence_probe.observe(binary, data) for source, _, data in records
+            }
+            profiles[name] = dict(
+                provenance=provenance,
+                training_artifact_hash=training["content_hash"] if training else None,
+                sources={
+                    source["id"]: dict(
+                        source=source,
+                        sample_sha256=sample["sha256"],
+                        byte_length=len(data),
+                        elapsed_ns=[],
+                    )
+                    for source, sample, data in records
+                },
+            )
+        # Build all models before timing. Rotate their order for every source/repetition.
+        for repeat in range(repeats):
+            for index, (source, _, data) in enumerate(records):
+                offset = (repeat + index) % len(NAMES)
+                for name in (*NAMES[offset:], *NAMES[:offset]):
+                    observed = sequence_probe.observe(binaries[name], data, iterations)
+                    timing = observed.pop("benchmark")
+                    if observed != baselines[name][source["id"]]:
+                        raise ValueError("timed run differs from untimed observation")
+                    profiles[name]["sources"][source["id"]]["elapsed_ns"].append(
+                        timing["elapsed_ns"]
+                    )
+    if affinity() != cpus or digest(library.read_bytes()) != library_hash:
+        raise ValueError("affinity/library changed during timing")
+    for profile in profiles.values():
+        for source in profile["sources"].values():
+            source["summary"] = summary(source["elapsed_ns"], iterations)
+        # Sum independent hot-document trials; do not present this as an interleaved corpus pass.
+        totals = [
+            sum(source["elapsed_ns"][i] for source in profile["sources"].values())
+            for i in range(repeats)
+        ]
+        profile["summed_document_trial_summary"] = summary(totals, iterations)
+    report = dict(
+        schema="native-model-timing-v1",
+        corpus_content_hash=manifest["content_hash"],
+        split=split,
+        scope="reused single prober: reset + filter + feed + confidence + checksum",
+        excluded="input I/O, allocation of input/scratch/prober, compilation, Python, output",
+        iterations=iterations,
+        repeats=repeats,
+        warmup_iterations=128,
+        clock="C++ steady_clock; nanoseconds",
+        cpu_affinity=cpus,
+        aggregate_policy=(
+            "sum of independent warmed same-document trial means; not interleaved corpus"
+        ),
+        environment=dict(
+            system=platform.system(),
+            release=platform.release(),
+            machine=platform.machine(),
+            cpu_before=cpu_info,
+            cpu_after=cpu_environment(cpus[0]),
+        ),
+        driver_dependencies={
+            path.name: digest(path.read_bytes())
+            for path in (Path(__file__), Path(native_comparison.__file__))
+        },
+        profiles=profiles,
+    )
+    report["content_hash"] = content_hash(report)
+    return report
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    for name in ("identity", "filtered", "manifest", "library", "output"):
+        parser.add_argument(name, type=Path)
+    parser.add_argument("--split", choices=("tuning", "validation"), default="validation")
+    parser.add_argument("--iterations", type=int, default=20000)
+    parser.add_argument("--repeats", type=int, default=7)
+    parser.add_argument("--cxx", default="c++")
+    args = parser.parse_args()
+
+    def load(path):
+        return json.loads(path.read_text(encoding="utf-8"))
+
+    report = run(
+        load(args.identity),
+        load(args.filtered),
+        load(args.manifest),
+        args.manifest.parent,
+        args.split,
+        args.library,
+        args.iterations,
+        args.repeats,
+        args.cxx,
+    )
+    write_idempotent(args.output, canonical(report))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/models/experimental/sequence-probe.cpp b/models/experimental/sequence-probe.cpp
index 3036393..9d65866 100644
--- a/models/experimental/sequence-probe.cpp
+++ b/models/experimental/sequence-probe.cpp
@@ -2,12 +2,14 @@
 // Independent observation harness. Detector/filter implementations stay in the library.
 #include "sequence-model.hpp"
 #include <algorithm>
+#include <chrono>
 #include <cstdint>
 #include <cstring>
 #include <fstream>
 #include <iomanip>
 #include <iostream>
 #include <stdexcept>
+#include <string>
 #include <vector>
 
 class SequenceProbe : public nsSingleByteCharSetProber {
@@ -39,7 +41,17 @@ class SequenceProbe : public nsSingleByteCharSetProber {
 
 int main(int argc, char** argv) {
   try {
-    if (argc != 2) throw std::runtime_error("usage: sequence-probe FILE");
+    if (argc != 2 && argc != 3)
+      throw std::runtime_error("usage: sequence-probe FILE [ITERATIONS]");
+    std::uint64_t iterations = 0;
+    if (argc == 3) {
+      const std::string argument(argv[2]);
+      if (argument.empty() || argument.find_first_not_of("0123456789") != std::string::npos)
+        throw std::runtime_error("iterations must be unsigned decimal");
+      iterations = std::stoull(argument);
+      if (iterations == 0 || iterations > 1000000)
+        throw std::runtime_error("iterations must be in [1, 1000000]");
+    }
     std::ifstream input(argv[1], std::ios::binary);
     if (!input) throw std::runtime_error("cannot open input");
     const std::size_t limit = 65536;
@@ -50,14 +62,34 @@ int main(int argc, char** argv) {
     if (data.size() > limit) throw std::runtime_error("input exceeds 65536 byte diagnostic limit");
     std::vector<char> buffer(std::max<std::size_t>(1, data.size()));
     PRUint32 retained = 0;
-    if (!data.empty()) {
-      nsCharSetProber::FilterWithoutEnglishLettersToBuffer(
-          data.data(), static_cast<PRUint32>(data.size()), buffer.data(), retained);
-    }
-    if (retained > data.size()) throw std::runtime_error("unexpected filter length");
     SequenceProbe probe(&uchardet_sequence_pilot::model);
-    // Match the SBCS group's empty-filter behavior. This is a single, non-reversed prober.
-    if (retained) probe.HandleData(buffer.data(), retained, nullptr, nullptr);
+    const auto run = [&]() {
+      probe.Reset();
+      retained = 0;
+      if (!data.empty()) {
+        nsCharSetProber::FilterWithoutEnglishLettersToBuffer(
+            data.data(), static_cast<PRUint32>(data.size()), buffer.data(), retained);
+      }
+      if (retained > data.size()) throw std::runtime_error("unexpected filter length");
+      // Match the SBCS group's empty-filter behavior; a single non-reversed prober.
+      if (retained) probe.HandleData(buffer.data(), retained, nullptr, nullptr);
+      const float confidence = probe.GetConfidence(0);
+      std::uint32_t bits = 0;
+      std::memcpy(&bits, &confidence, sizeof(bits));
+      return bits;
+    };
+    run();
+    std::int64_t elapsed_ns = 0;
+    volatile std::uint64_t checksum = 0;
+    const unsigned warmup = 128;
+    if (iterations) {
+      for (unsigned i = 0; i < warmup; ++i) checksum += run();
+      checksum = 0;
+      const auto start = std::chrono::steady_clock::now();
+      for (std::uint64_t i = 0; i < iterations; ++i) checksum += run();
+      elapsed_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(
+          std::chrono::steady_clock::now() - start).count();
+    }
     std::cout << "{\"schema\":\"sequence-native-probe-v1\",\"raw_bytes\":" << data.size()
               << ",\"filtered_bytes\":" << retained
               << ",\"model_encoding\":\"" << probe.GetCharSetName(0)
@@ -68,6 +100,12 @@ int main(int argc, char** argv) {
     std::cout << ",\"after_reset\":";
     probe.Reset();
     probe.print();
+    if (iterations) {
+      std::cout << ",\"benchmark\":{\"iterations\":" << iterations
+                << ",\"warmup_iterations\":" << warmup
+                << ",\"elapsed_ns\":" << elapsed_ns
+                << ",\"checksum\":" << checksum << '}';
+    }
     std::cout << "}\n";
     return std::cout ? 0 : 1;
   } catch (const std::exception& error) {
diff --git a/models/experimental/sequence_probe.py b/models/experimental/sequence_probe.py
index 5bef14f..d9db0f0 100644
--- a/models/experimental/sequence_probe.py
+++ b/models/experimental/sequence_probe.py
@@ -110,20 +110,30 @@ def _build(header, model_metadata, library, directory, compiler):
     return binary, provenance
 
 
-def observe(binary, data):
+def observe(binary, data, iterations=None):
     if len(data) > 65536:
         raise ValueError("probe input exceeds 65536 bytes")
+    if iterations is not None and (type(iterations) is not int or not 1 <= iterations <= 1000000):
+        raise ValueError("iterations must be an integer in [1, 1000000]")
     with tempfile.TemporaryDirectory(prefix="uchardet-sequence-input-") as temporary:
         path = Path(temporary) / "input.bin"
         path.write_bytes(data)
-        result = subprocess.run(
-            [str(binary), str(path)], check=True, capture_output=True, timeout=10
-        )
+        command = [str(binary), str(path)]
+        if iterations is not None:
+            command.append(str(iterations))
+        result = subprocess.run(command, check=True, capture_output=True, timeout=10)
     observation = json.loads(result.stdout)
     if observation.get("schema") != "sequence-native-probe-v1" or observation["raw_bytes"] != len(
         data
     ):
         raise ValueError("unexpected native observation")
+    if iterations is not None:
+        benchmark = observation["benchmark"]
+        if benchmark["iterations"] != iterations or benchmark["warmup_iterations"] != 128:
+            raise ValueError("unexpected native timing policy")
+        expected = int(observation["snapshot"]["confidence_bits"], 16) * iterations
+        if benchmark["elapsed_ns"] <= 0 or benchmark["checksum"] != expected:
+            raise ValueError("invalid native elapsed time/checksum")
     return observation
 
 
diff --git a/models/experimental/test_model_timing.py b/models/experimental/test_model_timing.py
new file mode 100644
index 0000000..511651d
--- /dev/null
+++ b/models/experimental/test_model_timing.py
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: MIT
+import unittest
+from unittest.mock import patch
+
+import model_timing
+
+
+class ModelTimingTests(unittest.TestCase):
+    def test_trial_summary_and_nearest_rank(self):
+        result = model_timing.summary([300, 100, 200], 10)
+        self.assertEqual(
+            result,
+            dict(
+                median_ns_per_iteration=20,
+                minimum_ns_per_iteration=10,
+                maximum_ns_per_iteration=30,
+                p95_trial_mean_ns_per_iteration=30,
+            ),
+        )
+        self.assertEqual(
+            model_timing.summary(list(range(1, 21)), 1)["p95_trial_mean_ns_per_iteration"], 19
+        )
+
+    def test_bad_times_and_iteration_counts(self):
+        for values in ([], [0], [-1], [True], [1.5]):
+            with self.assertRaises(ValueError):
+                model_timing.summary(values, 1)
+        for count in (0, -1, 1000001, True):
+            with self.assertRaises(ValueError):
+                model_timing.summary([1], count)
+
+    def test_requires_single_cpu(self):
+        with patch.object(model_timing.os, "sched_getaffinity", return_value={2, 3}, create=True):
+            with self.assertRaisesRegex(ValueError, "taskset"):
+                model_timing.affinity()
+        with patch.object(model_timing.os, "sched_getaffinity", return_value={2}, create=True):
+            self.assertEqual(model_timing.affinity(), [2])
+
+    def test_runner_configuration_rejected_before_corpus_or_compile(self):
+        for iterations, repeats in ((0, 7), (1, 2), (1, 32), (True, 7), (1, True)):
+            with self.assertRaises(ValueError):
+                model_timing.run(None, None, None, None, None, None, iterations, repeats)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/models/experimental/test_sequence_probe.py b/models/experimental/test_sequence_probe.py
index 688d812..e930c73 100644
--- a/models/experimental/test_sequence_probe.py
+++ b/models/experimental/test_sequence_probe.py
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: MIT
 import os
 import struct
+import subprocess
 import tempfile
 import unittest
 from pathlib import Path
@@ -12,6 +13,13 @@
 
 
 class SequenceProbeGuards(unittest.TestCase):
+    def test_iteration_limits_before_execution(self):
+        for iterations in (0, -1, 1000001, True, 1.5):
+            with patch.object(sequence_probe.subprocess, "run") as run:
+                with self.assertRaisesRegex(ValueError, "iterations"):
+                    sequence_probe.observe(Path("unused"), b"text", iterations)
+                run.assert_not_called()
+
     def test_input_limit_before_native_execution(self):
         with patch.object(sequence_probe.subprocess, "run") as run:
             with self.assertRaisesRegex(ValueError, "65536"):
@@ -108,6 +116,27 @@ def test_repeat_and_build_provenance(self):
                 self.contract, Path(os.environ["UCHARDET_STATIC_LIBRARY"]), self.temporary.name
             )
 
+    def test_timing_preserves_observation_and_checksum(self):
+        for data in (b"", b"ASCII", b"caf\xe9", b"\xe9\xe8\xe0"):
+            baseline = self.observed(data)
+            timed = sequence_probe.observe(self.binary, data, iterations=3)
+            benchmark = timed.pop("benchmark")
+            self.assertEqual(timed, baseline)
+            self.assertEqual(benchmark["iterations"], 3)
+            self.assertEqual(benchmark["warmup_iterations"], 128)
+            self.assertGreater(benchmark["elapsed_ns"], 0)
+            self.assertEqual(
+                benchmark["checksum"], 3 * int(baseline["snapshot"]["confidence_bits"], 16)
+            )
+
+    def test_native_iteration_argument_validation(self):
+        for argument in ("0", "-1", "1x", "1000001"):
+            result = subprocess.run(
+                [str(self.binary), "unused", argument], capture_output=True, text=True, timeout=10
+            )
+            self.assertNotEqual(result.returncode, 0)
+            self.assertIn("iterations", result.stderr)
+
 
 if __name__ == "__main__":
     unittest.main()