diff --git a/ab_rlc_test.sh b/ab_rlc_test.sh
index 3c8152f..2448ace 100644
--- a/ab_rlc_test.sh
+++ b/ab_rlc_test.sh
@@ -39,6 +39,51 @@ set -uo pipefail
 cd "$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "./_ir_fingerprint.sh"
 
+# RESCORE=<已有的 root>：判据改了之后，用当前的 ir_fingerprint 对盘上已有的 ttgir
+# 重新打分并改写该 root 的 screen.tsv，不重跑任何测量。
+#
+# 需要它是因为判据确实改过：_ir_fingerprint.sh 起初把 index.tsv 也算进哈希，后来又
+# 发现要抹掉开关自己盖的 ttg.rlc-* 属性。同一批 24 个算子，结论从 23 个 IR_CHANGED
+# 变成 16 个。重打分是秒级的，重跑那批筛选要 79 分钟。
+#
+# 原表存为 screen.tsv.before-rescore，判定有变化的算子逐个打出来。
+RESCORE="${RESCORE:-}"
+if [[ -n "$RESCORE" ]]; then
+  [[ -d "$RESCORE" ]] || { echo "!!! 目录不存在: $RESCORE" >&2; exit 2; }
+  TSV="$RESCORE/screen.tsv"
+  [[ -f "$TSV" ]] || { echo "!!! 没有 screen.tsv: $TSV" >&2; exit 2; }
+  cp "$TSV" "$TSV.before-rescore"
+
+  hdr=$(head -1 "$TSV.before-rescore")
+  # 列名 -> 序号，不写死列序
+  idx() { echo "$hdr" | tr '\t' '\n' | grep -nxF "$1" | cut -d: -f1; }
+  c_op=$(idx op); c_rb=$(idx rows_before); c_ra=$(idx rows_after); c_v=$(idx verdict)
+  [[ -n "$c_op" && -n "$c_v" ]] || { echo "!!! screen.tsv 缺 op/verdict 列" >&2; exit 2; }
+
+  printf '%s\n' "$hdr" > "$TSV"
+  changed=0
+  while IFS= read -r line; do
+    op=$(printf '%s' "$line" | cut -f"$c_op")
+    old=$(printf '%s' "$line" | cut -f"$c_v")
+    rb=$(printf '%s' "$line" | cut -f"${c_rb:-0}"); ra=$(printf '%s' "$line" | cut -f"${c_ra:-0}")
+    fa=$(ir_fingerprint "$RESCORE/${op}_before") || fa=""
+    fb=$(ir_fingerprint "$RESCORE/${op}_after")  || fb=""
+    if [[ "${rb:-0}" == 0 || "${ra:-0}" == 0 ]]; then v=NO_ROWS
+    elif [[ -z "$fa" || -z "$fb" ]]; then v=NO_TRITON
+    elif [[ "$fa" == "$fb" ]]; then v=NO_IR_DIFF
+    else v=IR_CHANGED; fi
+    printf '%s\n' "$line" | awk -v FS='\t' -v OFS='\t' -v i="$c_v" -v v="$v" '{$i=v; print}' >> "$TSV"
+    if [[ "$old" != "$v" ]]; then
+      printf '  %-22s %-12s -> %s\n' "$op" "$old" "$v" >&2
+      changed=$((changed+1))
+    fi
+  done < <(tail -n +2 "$TSV.before-rescore")
+
+  echo ">>> 重打分完成，$changed 个算子的判定变了；原表存为 $TSV.before-rescore"
+  awk -F'\t' 'NR>1{c[$NF]++} END{for (k in c) printf("  %-12s %d\n", k, c[k])}' "$TSV"
+  exit 0
+fi
+
 VENDOR="${VENDOR:-MUSA}"
 ENHANCE_VAR="FLAGTREE_${VENDOR}_RLC_ENHANCE"
 
diff --git a/partition.py b/partition.py
new file mode 100644
index 0000000..8eda301
--- /dev/null
+++ b/partition.py
@@ -0,0 +1,139 @@
+#!/usr/bin/env python3
+"""把筛选通过的算子按实测耗时分到各张卡上。
+
+为什么不用 `run_batch.py` 的 hash 分片：它按算子名的 hash 取模，不看重量。S5000 上
+17 个算子的六轮 campaign，hash 分片关键路径 120 分钟、有一张卡空转；按耗时贪心是
+70 分钟。同一批活，差 50 分钟。
+
+贪心（最长优先塞进当前最空的卡）在这里够用，也不可能更好：`topk` 一个算子就要 70.6
+分钟，而理想均分是 45.4——**关键路径的下界由最重的那个算子决定，加卡不解决**。分片
+只能保证除它之外的卡不空等。
+
+权重来自 `screen.tsv` 的 `elapsed_before + elapsed_after`（**一对 = 2 格**的秒数）。
+N 轮是 2N 格，所以预估耗时是权重的 N 倍——不是 N/6 倍，这里错过一次，把 topk 的 70.6
+分钟报成了 11.8。缺列时退化成等权重，并在 stderr 说明——等权重的分片仍然
+比不分好，但别让人以为它按耗时排过。
+
+用法：
+    python partition.py --screen runs/ab_rlc_XXX/screen.tsv --devices 0,1,2,3
+    python partition.py --screen ... --devices 0,1 --verdict IR_CHANGED --format shell
+"""
+
+from __future__ import annotations
+
+import argparse
+import csv
+import sys
+from pathlib import Path
+from typing import Dict, List, Optional, Sequence, Tuple
+
+Item = Tuple[str, float]
+
+
+def plan(items: Sequence[Item], slots: Sequence[str]) -> Dict[str, List[Item]]:
+    """最长优先贪心：每次把最重的活放进当前总量最小的卡。
+
+    卡少于 1 张是调用方的错，直接抛；活比卡少时后面的卡就是空的，这不是错误。
+    """
+    if not slots:
+        raise ValueError("需要至少一张卡")
+    out: Dict[str, List[Item]] = {s: [] for s in slots}
+    load: Dict[str, float] = {s: 0.0 for s in slots}
+    # 同重量时按名字排，保证同一份输入每次得到同一个方案
+    for name, weight in sorted(items, key=lambda kv: (-kv[1], kv[0])):
+        target = min(slots, key=lambda s: (load[s], s))
+        out[target].append((name, weight))
+        load[target] += weight
+    return out
+
+
+def imbalance(assignment: Dict[str, List[Item]]) -> float:
+    """最慢的卡 / 理想均分。1.0 是完美；下界由最重的单个算子决定。"""
+    loads = [sum(w for _, w in v) for v in assignment.values()]
+    total = sum(loads)
+    if total <= 0:
+        return 1.0
+    return max(loads) / (total / len(loads))
+
+
+def read_screen(path: Path, verdict: str = "IR_CHANGED"
+                ) -> Tuple[List[Item], Dict[str, str], List[str]]:
+    """(算子, 一对耗时秒), op -> op_file, 被判定挡掉的算子。"""
+    with path.open(newline="", encoding="utf-8") as f:
+        rows = list(csv.DictReader(f, delimiter="\t"))
+    if not rows:
+        raise SystemExit(f"筛选表没有数据行: {path}")
+    items: List[Item] = []
+    files: Dict[str, str] = {}
+    skipped: List[str] = []
+    warned = False
+    for r in rows:
+        op = r.get("op", "")
+        if not op:
+            continue
+        if verdict and r.get("verdict") != verdict:
+            skipped.append(f"{op}({r.get('verdict', '?')})")
+            continue
+        try:
+            w = float(r["elapsed_before"]) + float(r["elapsed_after"])
+        except (KeyError, TypeError, ValueError):
+            w = 1.0
+            if not warned:
+                print("!!! 筛选表没有 elapsed_* 列，退化成等权重分片——"
+                      "分片仍然比不分好，但它没有按耗时排过", file=sys.stderr)
+                warned = True
+        items.append((op, w))
+        files[op] = r.get("op_file") or op
+    return items, files, skipped
+
+
+def main(argv: Optional[List[str]] = None) -> int:
+    p = argparse.ArgumentParser(description=__doc__.splitlines()[0],
+                                formatter_class=argparse.RawDescriptionHelpFormatter)
+    p.add_argument("--screen", type=Path, required=True, help="ab_rlc_test.sh 的 screen.tsv")
+    p.add_argument("--devices", required=True, help="逗号分隔的设备列表，如 0,1,2,3")
+    p.add_argument("--verdict", default="IR_CHANGED",
+                   help="只取这个判定的算子；空字符串表示全要")
+    # 权重是一对（2 格）的秒数；N 轮是 2N 格，所以预估耗时是权重的 N 倍
+    p.add_argument("--rounds", type=int, default=6, help="仅用于打印预估耗时")
+    p.add_argument("--format", choices=("human", "shell"), default="human",
+                   help="shell 输出每卡一行 `<device>\\t<OPS>`，供驱动脚本读")
+    args = p.parse_args(argv)
+
+    if not args.screen.is_file():
+        raise SystemExit(f"筛选表不存在: {args.screen}")
+    devices = [d.strip() for d in args.devices.split(",") if d.strip()]
+    if not devices:
+        raise SystemExit("--devices 为空")
+
+    items, files, skipped = read_screen(args.screen, args.verdict)
+    if not items:
+        raise SystemExit(f"筛选表里没有 verdict={args.verdict} 的算子——"
+                         "先确认筛选跑过，且判据没有把所有算子都挡掉")
+
+    assignment = plan(items, devices)
+    if args.format == "shell":
+        for d in devices:
+            ops = " ".join(f"{op}:{files[op]}" for op, _ in assignment[d])
+            print(f"{d}\t{ops}")
+        return 0
+
+    total = sum(w for _, w in items) * args.rounds
+    print(f">>> {len(items)} 个算子 / {len(devices)} 张卡 / {args.rounds} 轮")
+    if skipped:
+        print(f">>> 判定挡掉 {len(skipped)} 个: {', '.join(skipped)}")
+    for d in devices:
+        load = sum(w for _, w in assignment[d]) * args.rounds
+        names = " ".join(op for op, _ in assignment[d]) or "（空）"
+        print(f"    卡{d}  {load/60:6.1f} 分钟  {names}")
+    crit = max(sum(w for _, w in v) for v in assignment.values()) * args.rounds
+    heaviest = max(items, key=lambda kv: kv[1])
+    print(f">>> 单卡串行 {total/3600:.2f} 小时；{len(devices)} 卡关键路径 "
+          f"{crit/60:.1f} 分钟，失衡 {imbalance(assignment):.2f}x")
+    print(f">>> 下界由最重的算子决定：{heaviest[0]} 单独就要 "
+          f"{heaviest[1]*args.rounds/60:.1f} 分钟，加卡不解决")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/test_backends.py b/test_backends.py
index d8bd9dc..6867f57 100644
--- a/test_backends.py
+++ b/test_backends.py
@@ -659,5 +659,80 @@ class ForeignVendorModuleTests(unittest.TestCase):
         self.assertEqual(foreign_vendor_modules("mthreads", mods), [])
 
 
+class PartitionTests(unittest.TestCase):
+    """按耗时把算子分到各卡。hash 分片在这批活上比它慢 50 分钟。"""
+
+    HEADER = "op\top_file\telapsed_before\telapsed_after\tverdict"
+
+    def _load(self, assignment):
+        return sorted(sum(w for _, w in v) for v in assignment.values())
+
+    def _screen(self, tmp, rows, header=None):
+        p = Path(tmp, "screen.tsv")
+        p.write_text((header or self.HEADER) + "\n" + "\n".join(rows) + "\n",
+                     encoding="utf-8")
+        return p
+
+    def test_heavy_first_keeps_cards_even(self):
+        from partition import plan
+        items = [("a", 10), ("b", 9), ("c", 8), ("d", 7), ("e", 6), ("f", 5)]
+        self.assertEqual(self._load(plan(items, ["0", "1", "2"])), [15, 15, 15])
+
+    def test_one_item_heavier_than_the_ideal_share_sets_the_floor(self):
+        # topk 单个 70 分钟、理想均分 45——加卡不解决，分片只保证别人不空等
+        from partition import imbalance, plan
+        items = [("topk", 70)] + [(f"op{i}", 5) for i in range(10)]
+        a = plan(items, [str(i) for i in range(8)])
+        self.assertEqual(max(sum(w for _, w in v) for v in a.values()), 70)
+        self.assertGreater(imbalance(a), 1.0)
+
+    def test_more_cards_than_operators_leaves_some_empty(self):
+        from partition import plan
+        a = plan([("a", 1), ("b", 1)], ["0", "1", "2", "3"])
+        self.assertEqual(sum(1 for v in a.values() if not v), 2)
+
+    def test_same_input_gives_the_same_plan(self):
+        from partition import plan
+        items = [("a", 5), ("b", 5), ("c", 5), ("d", 5)]
+        first = plan(items, ["0", "1"])
+        for _ in range(5):
+            self.assertEqual(plan(list(reversed(items)), ["0", "1"]), first)
+
+    def test_no_cards_is_the_callers_error(self):
+        from partition import plan
+        with self.assertRaises(ValueError):
+            plan([("a", 1)], [])
+
+    def test_perfect_balance_is_one(self):
+        from partition import imbalance, plan
+        self.assertEqual(imbalance(plan([("a", 5), ("b", 5)], ["0", "1"])), 1.0)
+
+    def test_verdict_filters_and_reports_what_it_dropped(self):
+        from partition import read_screen
+        with tempfile.TemporaryDirectory() as tmp:
+            f = self._screen(tmp, ["a\ta\t10\t10\tIR_CHANGED",
+                                   "b\tbb\t5\t5\tNO_IR_DIFF",
+                                   "c\tc\t1\t1\tNO_TRITON"])
+            items, files, skipped = read_screen(f)
+            self.assertEqual(items, [("a", 20.0)])
+            self.assertEqual(files["a"], "a")
+            self.assertEqual(len(skipped), 2)
+
+    def test_op_file_defaults_to_op_name(self):
+        from partition import read_screen
+        with tempfile.TemporaryDirectory() as tmp:
+            f = self._screen(tmp, ["a\t\t1\t1\tIR_CHANGED"])
+            _, files, _ = read_screen(f)
+            self.assertEqual(files["a"], "a")
+
+    def test_missing_elapsed_falls_back_to_equal_weights(self):
+        from partition import read_screen
+        with tempfile.TemporaryDirectory() as tmp:
+            f = self._screen(tmp, ["a\ta\tIR_CHANGED", "b\tb\tIR_CHANGED"],
+                             header="op\top_file\tverdict")
+            items, _, _ = read_screen(f)
+            self.assertEqual([w for _, w in items], [1.0, 1.0])
+
+
 if __name__ == "__main__":
     unittest.main()