diff --git a/README.md b/README.md
index 826003f..3391c47 100644
--- a/README.md
+++ b/README.md
@@ -237,6 +237,19 @@ failed replay_fallback no_cudagraph capture_poisoned`。README 要求必查的
 想起来的时候才发生。每格另有 `CELL_TIMEOUT`（默认 2400 秒）兜底，超时记 `rc=124` 并打
 `!!! CELL_TIMEOUT`，不会让一格卡死拖住整批。
 
+全程还采一份 `<root>/telemetry.tsv`：
+
+```
+timestamp            index  sm_clock_mhz  mem_clock_mhz  temp_c  power_w  util_pct
+2026-09-10T07:41:12  7      1888          2500           36      477.68   87
+```
+
+列在 cuda 与 musa 上完全一致（`nvidia-smi --query-gpu` 与 `mthreads-gmi -q --json`
+各自解析后归一），所以两台机器的 campaign 可以并排读。理由很直接：六轮 A/B 声称的是
+0.01% 量级的单侧噪声，**降频和热漂移能移动比这大得多的延迟，而且在 run.log 里不留
+任何痕迹**——报告照样干净。`TELEMETRY_INTERVAL`（默认 5 秒）设 0 关闭；采样器缺失或
+没权限时 `telemetry.py` 安静退出并把原因写进 `telemetry.err`，不影响测试本身。
+
 第 1 轮 A/B 跑完后，脚本比两侧 `ttgir/` 的指纹（相对路径 + 内容）。**逐字节相同就
 跳过这个算子**，并打 `!!! SWITCH_NO_IR_DIFF op=... switch=...`：这个开关没改变该算子的
 生成代码，剩下 N-1 轮测的全是噪声，最后还会报成一个"无差异"的结论。先查开关名拼写
diff --git a/ab_repeat.sh b/ab_repeat.sh
index 6e70c1c..44ca537 100644
--- a/ab_repeat.sh
+++ b/ab_repeat.sh
@@ -57,6 +57,19 @@ ROOT="runs/ab_repeat_${SWITCH}_$(date +%Y%m%d-%H%M%S)"
 mkdir -p "$ROOT"
 LOG="$ROOT/summary.log"
 STATUS="$ROOT/status.tsv"
+
+# 全程采时钟/温度/功耗。六轮 A/B 声称的是 0.01% 量级的单侧噪声，降频和热漂移
+# 能移动比这大得多的延迟，而且在 run.log 里不留痕迹——报告照样干净。
+# TELEMETRY_INTERVAL=0 关闭。采不到时 telemetry.py 自己安静退出，不影响测试。
+TELEMETRY_INTERVAL="${TELEMETRY_INTERVAL:-5}"
+TELE_PID=""
+if [[ "$TELEMETRY_INTERVAL" != "0" ]]; then
+  python telemetry.py --backend "${ZL_BACKEND:-cuda}" --device "${ZL_DEVICE:-}" \
+    --interval "$TELEMETRY_INTERVAL" --run \
+    > "$ROOT/telemetry.tsv" 2> "$ROOT/telemetry.err" &
+  TELE_PID=$!
+  trap '[[ -n "$TELE_PID" ]] && kill "$TELE_PID" 2>/dev/null' EXIT
+fi
 printf 'round\top\tside\tswitch\trc\telapsed_s\tsuccess\tfailed\treplay_fallback\tno_cudagraph\tcapture_poisoned\n' > "$STATUS"
 
 # 跑一格并逐格登记。事后 grep 也能拿到这些数，但只在有人想起来时才发生；
@@ -157,5 +170,7 @@ sed -i -E $'s/\x1b\\[[0-9;]*[A-Za-z]//g' "$LOG"
 
 echo ">>> 总 log: $(pwd)/$LOG"
 echo ">>> 逐格状态表: $(pwd)/$STATUS"
+[[ -s "$ROOT/telemetry.tsv" ]] && echo ">>> 时钟/温度: $(pwd)/$ROOT/telemetry.tsv"
+[[ -s "$ROOT/telemetry.err" ]] && echo ">>> 遥测提示: $(cat "$ROOT/telemetry.err")"
 echo ">>> 逐算子重出报告: python batch_summary.py --ab-rounds $ROOT/<op> --label <op>"
 echo ">>> 解读要点: 逐轮区间宽说明判定不稳；单侧噪声大说明机器不稳；两者含义不同"
diff --git a/backends/base.py b/backends/base.py
index c1afae7..21618a0 100644
--- a/backends/base.py
+++ b/backends/base.py
@@ -72,6 +72,34 @@ class DeviceBackend:
     # backend. Skipped up front so one of them cannot cost a whole run.
     capture_deny_ops: Tuple[str, ...] = ()
 
+    # One-shot device telemetry sampler. Empty means this backend has none, and
+    # the campaign runs without a clock/thermal record rather than pretending.
+    # "{dev}" is dropped from the argv when no device is pinned, so the sampler
+    # covers every visible device instead of guessing an index.
+    telemetry_argv: Tuple[str, ...] = ()
+
+    def telemetry_command(self, device: str = "") -> List[str]:
+        if not self.telemetry_argv:
+            return []
+        out: List[str] = []
+        for a in self.telemetry_argv:
+            if "{dev}" in a:
+                if not device:
+                    # Drop the flag the placeholder belonged to as well; a bare
+                    # trailing "-i" makes the sampler fail instead of widening.
+                    if out and out[-1].startswith("-"):
+                        out.pop()
+                    continue
+                a = a.replace("{dev}", device)
+            out.append(a)
+        return out
+
+    def parse_telemetry(self, raw: str) -> List[Dict[str, str]]:
+        """One dict per device: index, sm_clock_mhz, mem_clock_mhz, temp_c,
+        power_w, util_pct. Normalised so a CUDA and a MUSA campaign produce the
+        same columns and can be read side by side."""
+        return []
+
     def classify_capture_error(self, exc: BaseException) -> str:
         """-> "fatal" | "poisoned" | "recoverable".
 
diff --git a/backends/cuda.py b/backends/cuda.py
index 0c3ae54..8429382 100644
--- a/backends/cuda.py
+++ b/backends/cuda.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Dict, List
+
 from .base import DeviceBackend
 
 
@@ -26,3 +28,22 @@ class CudaBackend(DeviceBackend):
     # No CUDA wording is known to poison the context without also matching one
     # of the fatal markers above, so nothing is listed here rather than guessed.
     poisoning_error_markers = ()
+
+    telemetry_argv = (
+        "nvidia-smi",
+        "--query-gpu=index,clocks.sm,clocks.mem,temperature.gpu,power.draw,utilization.gpu",
+        "--format=csv,noheader,nounits",
+        "-i", "{dev}",
+    )
+
+    def parse_telemetry(self, raw: str) -> List[Dict[str, str]]:
+        out: List[Dict[str, str]] = []
+        for line in raw.splitlines():
+            parts = [p.strip() for p in line.split(",")]
+            if len(parts) != 6 or not parts[0].isdigit():
+                continue
+            out.append(dict(zip(
+                ("index", "sm_clock_mhz", "mem_clock_mhz",
+                 "temp_c", "power_w", "util_pct"), parts)))
+        return out
+
diff --git a/backends/musa.py b/backends/musa.py
index 066af8d..a0dbfbf 100644
--- a/backends/musa.py
+++ b/backends/musa.py
@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Dict, List
+
 from .base import DeviceBackend
 
 
@@ -50,3 +52,50 @@ class MusaBackend(DeviceBackend):
     # Device count comes from torch.musa or MUSA_VISIBLE_DEVICES. Do not guess
     # a vendor CLI here; confirm the real listing tool before adding it.
     list_command = None
+
+    # mthreads-gmi has no CSV query mode; --json is the only machine-readable
+    # form it offers. Values arrive with their units glued on ("36C", "1888MHz",
+    # "477.68W", "87%"), so the parser strips trailing non-numerics rather than
+    # trusting a fixed suffix.
+    telemetry_argv = (
+        "mthreads-gmi", "-q",
+        "-d", "TEMPERATURE,CLOCK,POWER,UTILIZATION",
+        "--json",
+        "-i", "{dev}",
+    )
+
+    def parse_telemetry(self, raw: str) -> List[Dict[str, str]]:
+        import json
+        import re
+
+        def num(v):
+            m = re.match(r"^\s*(-?[\d.]+)", str(v or ""))
+            return m.group(1) if m else ""
+
+        start = raw.find("{")
+        if start < 0:
+            return []
+        try:
+            data = json.loads(raw[start:])
+        except Exception:
+            return []
+        gpus = data.get("GPU") or []
+        if isinstance(gpus, dict):
+            gpus = [gpus]
+        out: List[Dict[str, str]] = []
+        for g in gpus:
+            clocks = g.get("Clocks") or {}
+            power = g.get("Power Readings") or {}
+            # 键名带尾随空格（"Power Draw "），别按字面写死
+            draw = next((v for k, v in power.items()
+                         if k.strip() == "Power Draw"), "")
+            out.append({
+                "index": str(g.get("Index", "")).strip(),
+                "sm_clock_mhz": num(clocks.get("Graphics")),
+                "mem_clock_mhz": num(clocks.get("Memory")),
+                "temp_c": num((g.get("Temperature") or {}).get("GPU Current Temp")),
+                "power_w": num(draw),
+                "util_pct": num((g.get("Utilization") or {}).get("Gpu")),
+            })
+        return out
+
diff --git a/telemetry.py b/telemetry.py
new file mode 100644
index 0000000..0ba1fdd
--- /dev/null
+++ b/telemetry.py
@@ -0,0 +1,99 @@
+#!/usr/bin/env python3
+"""采样设备时钟/温度/功耗，跨后端归一化成同一组列。
+
+为什么要有它：六轮 A/B 会声称单侧噪声在 0.01% 量级。降频和热漂移足以移动比这大
+得多的延迟，而且在 run.log 里不留任何痕迹——报告照样干净。NV 上复现 PR763 的那次
+全程 `nvidia-smi -l 5` 写 clocks.csv，S5000 这边一直没有对应的东西。
+
+输出每设备每次采样一行 TSV：
+
+    timestamp  index  sm_clock_mhz  mem_clock_mhz  temp_c  power_w  util_pct
+
+列在 cuda 与 musa 上完全一致，所以两边的 campaign 可以并排读。采样器不存在时安静
+退出：拿不到遥测是缺一份证据，不是让整批测试失败的理由。
+
+用法：
+    python telemetry.py --backend musa --device 7 --interval 5 --run > telemetry.tsv
+    python telemetry.py --backend cuda            # 只打印将要执行的采样命令
+"""
+
+from __future__ import annotations
+
+import argparse
+import os
+import subprocess
+import sys
+import time
+from typing import List, Optional
+
+FIELDS = ("index", "sm_clock_mhz", "mem_clock_mhz", "temp_c", "power_w", "util_pct")
+
+
+def resolve_device(backend, explicit: Optional[str]) -> str:
+    """显式设备优先，否则从后端自己的可见性变量取。
+
+    单值才用得上：`MUSA_VISIBLE_DEVICES=7` 指一张卡，`0,1,2` 指一组，后者不传
+    `-i`、采全部，比挑第一张更诚实。
+    """
+    if explicit:
+        return explicit.strip()
+    for key in getattr(backend, "visibility_env_keys", ()):
+        raw = os.environ.get(key, "").strip()
+        if raw and "," not in raw:
+            return raw
+    return ""
+
+
+def sample_once(backend, argv: List[str]) -> List[dict]:
+    try:
+        out = subprocess.run(argv, capture_output=True, text=True, timeout=30)
+    except (OSError, subprocess.SubprocessError):
+        return []
+    return backend.parse_telemetry(out.stdout or "")
+
+
+def run(backend, device: str, interval: float, out=sys.stdout) -> int:
+    argv = backend.telemetry_command(device)
+    if not argv:
+        print(f"[telemetry] backend={backend.name} 没有采样器；本批不记时钟/温度",
+              file=sys.stderr, flush=True)
+        return 0
+    if not sample_once(backend, argv):
+        # 第一次就取不到，说明工具缺失或没权限。不要留一个空文件让人以为采过了
+        print(f"[telemetry] {argv[0]} 取不到读数；本批不记时钟/温度",
+              file=sys.stderr, flush=True)
+        return 0
+    print("timestamp\t" + "\t".join(FIELDS), file=out, flush=True)
+    while True:
+        ts = time.strftime("%Y-%m-%dT%H:%M:%S")
+        for row in sample_once(backend, argv):
+            print(ts + "\t" + "\t".join(row.get(f, "") for f in FIELDS),
+                  file=out, flush=True)
+        time.sleep(interval)
+
+
+def main(argv: Optional[List[str]] = None) -> int:
+    p = argparse.ArgumentParser(description=__doc__,
+                                formatter_class=argparse.RawDescriptionHelpFormatter)
+    p.add_argument("--backend", default=os.environ.get("ZL_BACKEND", "cuda"))
+    p.add_argument("--device", default=os.environ.get("ZL_DEVICE", ""))
+    p.add_argument("--interval", type=float, default=5.0)
+    p.add_argument("--run", action="store_true",
+                   help="持续采样直到被杀；不给则只打印采样命令")
+    args = p.parse_args(argv)
+
+    sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+    from backends import get_backend
+    backend = get_backend(args.backend)
+    device = resolve_device(backend, args.device)
+    if not args.run:
+        print(" ".join(backend.telemetry_command(device)))
+        return 0
+    try:
+        return run(backend, device, args.interval)
+    except KeyboardInterrupt:
+        return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/test_backends.py b/test_backends.py
index 03e7315..0f6baed 100644
--- a/test_backends.py
+++ b/test_backends.py
@@ -541,5 +541,78 @@ class CaliberGuardTests(unittest.TestCase):
                 len(report_ab(a / "run.log", b / "run.log", "op", strict=False)), 1)
 
 
+class TelemetryTests(unittest.TestCase):
+    """采样器命令与解析。两边归一到同一组列，campaign 才能并排读。"""
+
+    # 取自 S5000 实机：值带单位，"Power Draw " 的键名有尾随空格
+    MUSA_JSON = """
+{
+    "Attached GPUs": "8",
+    "GPU": [
+        {
+            "Index": "7",
+            "Temperature": {"GPU Current Temp": "36C"},
+            "Clocks": {"Graphics": "1888MHz", "Memory": "2500MHz", "Video": "0MHz"},
+            "Power Readings": {"Power Draw ": "477.68W", "Current Power Limit": "950.00W"},
+            "Utilization": {"Gpu": "87%", "Memory": "14%"}
+        }
+    ]
+}
+"""
+    CUDA_CSV = "0, 1980, 2619, 41, 122.35, 63\n"
+
+    def test_musa_parses_units_off_values(self):
+        rows = get_backend("musa").parse_telemetry(self.MUSA_JSON)
+        self.assertEqual(rows, [{
+            "index": "7", "sm_clock_mhz": "1888", "mem_clock_mhz": "2500",
+            "temp_c": "36", "power_w": "477.68", "util_pct": "87"}])
+
+    def test_cuda_parses_csv(self):
+        rows = get_backend("cuda").parse_telemetry(self.CUDA_CSV)
+        self.assertEqual(rows, [{
+            "index": "0", "sm_clock_mhz": "1980", "mem_clock_mhz": "2619",
+            "temp_c": "41", "power_w": "122.35", "util_pct": "63"}])
+
+    def test_both_backends_yield_the_same_columns(self):
+        import telemetry
+        a = get_backend("musa").parse_telemetry(self.MUSA_JSON)[0]
+        b = get_backend("cuda").parse_telemetry(self.CUDA_CSV)[0]
+        self.assertEqual(set(a), set(b))
+        self.assertEqual(set(a), set(telemetry.FIELDS))
+
+    def test_garbage_parses_to_nothing_rather_than_raising(self):
+        for backend in ("musa", "cuda"):
+            for raw in ("", "no such tool", "{broken json"):
+                self.assertEqual(get_backend(backend).parse_telemetry(raw), [])
+
+    def test_no_device_drops_the_flag_not_just_the_value(self):
+        # 留下裸 "-i" 会让采样器直接失败，比采全部更糟
+        argv = get_backend("musa").telemetry_command("")
+        self.assertNotIn("-i", argv)
+        self.assertIn("--json", argv)
+        self.assertEqual(get_backend("musa").telemetry_command("7")[-2:], ["-i", "7"])
+
+    def test_backend_without_sampler_returns_empty(self):
+        from backends.base import DeviceBackend
+        self.assertEqual(DeviceBackend().telemetry_command("0"), [])
+
+    def test_device_comes_from_the_visibility_var_when_unpinned(self):
+        import telemetry
+        backend = get_backend("musa")
+        old = os.environ.get("MUSA_VISIBLE_DEVICES")
+        try:
+            os.environ["MUSA_VISIBLE_DEVICES"] = "7"
+            self.assertEqual(telemetry.resolve_device(backend, ""), "7")
+            # 一组卡不挑第一张，交给采样器采全部
+            os.environ["MUSA_VISIBLE_DEVICES"] = "0,1,2"
+            self.assertEqual(telemetry.resolve_device(backend, ""), "")
+            self.assertEqual(telemetry.resolve_device(backend, "3"), "3")
+        finally:
+            if old is None:
+                os.environ.pop("MUSA_VISIBLE_DEVICES", None)
+            else:
+                os.environ["MUSA_VISIBLE_DEVICES"] = old
+
+
 if __name__ == "__main__":
     unittest.main()