diff --git a/docs/flashsac_optimization_report_zh.md b/docs/flashsac_optimization_report_zh.md
new file mode 100644
index 000000000..d284ba0e0
--- /dev/null
+++ b/docs/flashsac_optimization_report_zh.md
@@ -0,0 +1,41 @@
+# FlashSAC 优化简报
+
+## 改了什么
+
+之前的 FlashSAC 优化把编译边界从单独的 loss 扩大到完整 objective，让 Inductor 可以跨越网络前向、categorical target 和 loss 进行融合；同时保留 graph-safe 的固定输出与延迟 metrics 拷贝，避免 CUDA Graph replay 覆盖正在使用的地址。
+
+## 为什么有效
+
+原路径会产生多个小 kernel 和中间 tensor。完整 objective compile 减少了 launch 和中间读写，固定输出则避免编译器临时 buffer 与 metrics buffer 复用同一地址。collector 仍然使用真实环境进程，learner 继续在 GPU 上更新。
+
+## 怎么看真实训练耗时
+
+```bash
+uv run scripts/benchmark/rl/benchmark_flashsac_training.py \
+  --backend mujoco --iterations 20 --num-envs 256 \
+  --uni-rl-src ../unilab_rl-flashsac-optimization/src \
+  --output scripts/benchmark/outputs/flashsac_training/summary.json
+```
+
+脚本会显示每轮的：
+
+```text
+step    learner(ms)  collector(ms)  iter(ms)  reward
+...
+```
+
+结尾输出三组 mean、median、p90、p95。这里的 collector 时间来自真实 MuJoCo/Motrix `env.step()`，不是预生成 action 的离线测试；learner 时间来自真实 FlashSAC update。
+
+## 结果解释
+
+总轮时间不是 learner 和 collector 的简单串行相加，因为 double-buffer runner 会让两者部分重叠。判断优化是否有效，应比较同一 backend、task、num_envs、batch、iterations 下的完整 `iter_ms`，同时观察 learner 和 collector 两列，避免只看其中一个阶段。
+
+本机用 G1WalkFlat + MuJoCo 做了短跑验证（16 env，batch 16，1 update/step）。eager 路径的 5 个有效样本结果为：learner `6.572 / 6.219 / 7.338 / 7.520 ms`，collector `49.814 / 9.006 / 123.028 / 140.249 ms`，总轮 `7.446 / 7.048 / 8.324 / 8.545 ms`（依次为 mean / median / p90 / p95）。开启 full-objective compile 后，去掉前 4 个编译/预热样本，3 个 steady-state 样本为：learner `2.217 / 2.215 / 2.265 / 2.271 ms`，collector `4.110 / 3.914 / 4.529 / 4.606 ms`，总轮 `3.015 / 3.020 / 3.061 / 3.066 ms`。样本很少，这组数字用于验证计时链路，不作为正式跨配置结论。
+
+## 复现注意事项
+
+- 需要安装 UniLab 对应的物理 backend extra；MuJoCo 是最容易复现的选择。
+- 测试前先确认 `unilab_rl` 版本，推荐使用 `--uni-rl-src` 指向包含 FlashSAC 优化提交的 checkout。
+- 首轮可能包含 torch.compile 编译开销；比较 steady state 时应增加 iterations，并丢弃最初的编译/预热轮次。
+- 脚本可用 `--skip-first N` 丢弃前 N 条 timing 样本，JSON 仍保留完整的 `rows_all`。
+- 本报告不包含 Triton categorical-target 实验；Triton 仍是单独的可选实验目录。
diff --git a/scripts/benchmark/rl/README_flashsac_training.md b/scripts/benchmark/rl/README_flashsac_training.md
new file mode 100644
index 000000000..f4b2cc854
--- /dev/null
+++ b/scripts/benchmark/rl/README_flashsac_training.md
@@ -0,0 +1,55 @@
+# FlashSAC 真实训练计时
+
+`benchmark_flashsac_training.py` 会调用生产入口 `train_flashsac.py`，创建真实物理后端环境，并实时转发训练输出。训练结束后，它从同一次训练的 TensorBoard 日志中打印：
+
+- 每轮 learner update 时间；
+- 每轮 collector cycle 时间（环境步进、replay 写入和 bookkeeping）；
+- 每轮总时间和 reward；
+- learner、collector、总时间的 mean / median / p90 / p95。
+
+## 运行
+
+MuJoCo：
+
+```bash
+uv run scripts/benchmark/rl/benchmark_flashsac_training.py \
+  --backend mujoco --iterations 20 --num-envs 256 \
+  --output scripts/benchmark/outputs/flashsac_training/summary.json
+```
+
+Motrix：
+
+```bash
+uv run scripts/benchmark/rl/benchmark_flashsac_training.py \
+  --backend motrix --iterations 20 --num-envs 256
+```
+
+默认开启之前 FlashSAC 优化使用的 full-objective compile。要测 eager 路径，使用 `--no-compile`。如果要明确使用本地的优化版 `unilab_rl` checkout：
+
+```bash
+uv run scripts/benchmark/rl/benchmark_flashsac_training.py \
+  --uni-rl-src ../unilab_rl-flashsac-optimization/src \
+  --backend mujoco --iterations 20 --num-envs 256
+```
+
+compile 首轮可能包含编译开销；要只看 steady-state，可排除前几条共同 timing 样本：
+
+```bash
+... --skip-first 4
+```
+
+JSON 同时保留未过滤的 `rows_all` 和用于统计的 `rows`。
+
+实际训练日志会保存在 `scripts/benchmark/outputs/flashsac_training/<timestamp>/`，可以直接用 TensorBoard 查看：
+
+```bash
+uv run tensorboard --logdir scripts/benchmark/outputs/flashsac_training
+```
+
+`--task` 可替换为其他 FlashSAC owner task，只要对应的 `<task>/<backend>.yaml` 存在。`--extra-override key=value` 可以追加 Hydra 参数，例如：
+
+```bash
+--extra-override training.torch_threads.learner_num_threads=8
+```
+
+注意：这不是模型或 collector 的仿真 microbenchmark，而是完整的 collector→replay→learner 训练链路；collector 时间来自真实物理后端的 `env.step()`。
diff --git a/scripts/benchmark/rl/benchmark_flashsac_training.py b/scripts/benchmark/rl/benchmark_flashsac_training.py
new file mode 100644
index 000000000..ba362b5ca
--- /dev/null
+++ b/scripts/benchmark/rl/benchmark_flashsac_training.py
@@ -0,0 +1,279 @@
+#!/usr/bin/env python3
+"""Run a real FlashSAC training loop and report learner/collector timing.
+
+Unlike the collector-only benchmark, this command launches the production
+``train_flashsac.py`` entrypoint, constructs the selected physics backend, and
+reads the timing scalars emitted by the real off-policy runner.  The child
+process output is forwarded live so the user can see training progress.
+
+Example (MuJoCo):
+
+    uv run scripts/benchmark/rl/benchmark_flashsac_training.py \
+        --backend mujoco --iterations 20 --num-envs 256
+
+The same command works with ``--backend motrix`` when the Motrix extra is
+installed.  Use ``--uni-rl-src`` to test a local unilab-rl checkout instead of
+the installed package, for example the FlashSAC optimization branch.
+"""
+
+from __future__ import annotations
+
+import argparse
+import json
+import os
+import subprocess
+import sys
+from dataclasses import dataclass
+from datetime import datetime
+from pathlib import Path
+from statistics import fmean
+from typing import Iterable, Sequence
+
+ROOT_DIR = Path(__file__).resolve().parents[3]
+TRAIN_SCRIPT = ROOT_DIR / "src" / "unilab" / "scripts" / "train_flashsac.py"
+DEFAULT_OUTPUT_ROOT = ROOT_DIR / "scripts" / "benchmark" / "outputs" / "flashsac_training"
+if str(ROOT_DIR) not in sys.path:
+    sys.path.insert(0, str(ROOT_DIR))
+
+from scripts.benchmark.core.device_info import get_device_info_dict
+
+
+@dataclass(frozen=True)
+class Scalar:
+    step: int
+    value: float
+
+
+def _percentile(values: Sequence[float], quantile: float) -> float:
+    if not values:
+        raise ValueError("cannot calculate a percentile of an empty sequence")
+    ordered = sorted(float(value) for value in values)
+    position = (len(ordered) - 1) * quantile
+    lower = int(position)
+    upper = min(lower + 1, len(ordered) - 1)
+    return ordered[lower] + (position - lower) * (ordered[upper] - ordered[lower])
+
+
+def summarize(values: Iterable[float]) -> dict[str, float | int]:
+    samples = [float(value) for value in values]
+    if not samples:
+        raise ValueError("no timing samples were emitted")
+    return {
+        "count": len(samples),
+        "mean_ms": fmean(samples),
+        "median_ms": _percentile(samples, 0.50),
+        "p90_ms": _percentile(samples, 0.90),
+        "p95_ms": _percentile(samples, 0.95),
+        "min_ms": min(samples),
+        "max_ms": max(samples),
+    }
+
+
+def _event_file(run_dir: Path) -> Path:
+    candidates = sorted(run_dir.rglob("events.out.tfevents.*"))
+    if not candidates:
+        raise RuntimeError(f"no TensorBoard event file found under {run_dir}")
+    return candidates[-1]
+
+
+def _read_scalars(run_dir: Path, tag: str) -> list[Scalar]:
+    from tensorboard.backend.event_processing import event_accumulator
+
+    accumulator = event_accumulator.EventAccumulator(str(_event_file(run_dir)))
+    accumulator.Reload()
+    if tag not in accumulator.Tags().get("scalars", []):
+        return []
+    return [Scalar(int(event.step), float(event.value)) for event in accumulator.Scalars(tag)]
+
+
+def _by_step(samples: Sequence[Scalar]) -> dict[int, float]:
+    return {sample.step: sample.value for sample in samples}
+
+
+def parse_timing(run_dir: Path, *, skip_first: int = 0) -> dict[str, object]:
+    """Read per-iteration learner, collector, wall and reward timings."""
+    learner = _read_scalars(run_dir, "timing/learner_train_ms")
+    collector = _read_scalars(run_dir, "perf/collector_cycle_ms")
+    wall = _read_scalars(run_dir, "perf/iter_ms")
+    reward = _read_scalars(run_dir, "reward/mean")
+    if not learner:
+        raise RuntimeError("training log has no timing/learner_train_ms samples")
+    if not collector:
+        # Older runners do not have the aggregate scalar, but emit the three
+        # mutually exclusive collector phases.  Reconstruct the cycle exactly.
+        phases = [
+            _by_step(_read_scalars(run_dir, f"timing/collector_{name}"))
+            for name in ("env_step_ms", "replay_ms", "bookkeeping_ms")
+        ]
+        steps = sorted(set().union(*(phase.keys() for phase in phases)))
+        collector = [Scalar(step, sum(phase.get(step, 0.0) for phase in phases)) for step in steps]
+    if not collector:
+        raise RuntimeError("training log has no collector timing samples")
+
+    learner_by_step = _by_step(learner)
+    collector_by_step = _by_step(collector)
+    wall_by_step = _by_step(wall)
+    reward_by_step = _by_step(reward)
+    steps = sorted(set(learner_by_step) & set(collector_by_step))
+    rows_all = [
+        {
+            "step": step,
+            "learner_train_ms": learner_by_step[step],
+            "collector_cycle_ms": collector_by_step[step],
+            "iter_ms": wall_by_step.get(step),
+            "reward": reward_by_step.get(step),
+        }
+        for step in steps
+    ]
+    if skip_first < 0:
+        raise ValueError("skip_first must be non-negative")
+    rows = rows_all[skip_first:]
+    if not rows:
+        raise RuntimeError(
+            f"learner and collector timing series have fewer than {skip_first + 1} common steps"
+        )
+    return {
+        "num_samples": len(rows),
+        "num_samples_all": len(rows_all),
+        "skip_first": skip_first,
+        "rows_all": rows_all,
+        "learner_train_ms": summarize(row["learner_train_ms"] for row in rows),
+        "collector_cycle_ms": summarize(row["collector_cycle_ms"] for row in rows),
+        "iter_ms": summarize(row["iter_ms"] for row in rows if row["iter_ms"] is not None),
+        "rows": rows,
+    }
+
+
+def _command(args: argparse.Namespace, run_dir: Path) -> list[str]:
+    task = f"{args.task}/{args.backend}"
+    command = [
+        sys.executable,
+        str(TRAIN_SCRIPT),
+        f"task={task}",
+        "training.no_play=true",
+        f"training.sim_backend={args.backend}",
+        f"training.log_dir={run_dir}",
+        f"algo.max_iterations={args.iterations}",
+        f"algo.num_envs={args.num_envs}",
+        f"algo.batch_size={args.batch_size}",
+        f"algo.replay_buffer_n={args.replay_buffer_n}",
+        f"algo.learning_starts={args.learning_starts}",
+        f"algo.updates_per_step={args.updates_per_step}",
+        "algo.save_interval=1000000",
+        f"algo.algo_params.use_compile={str(args.compile).lower()}",
+        f"algo.algo_params.compile_full_objectives={str(args.compile).lower()}",
+    ]
+    command.extend(args.extra_override)
+    return command
+
+
+def _run(command: Sequence[str], *, env: dict[str, str]) -> None:
+    print("$ " + " ".join(command), flush=True)
+    process = subprocess.Popen(
+        list(command),
+        cwd=ROOT_DIR,
+        env=env,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        text=True,
+        bufsize=1,
+    )
+    assert process.stdout is not None
+    for line in process.stdout:
+        print(line, end="", flush=True)
+    return_code = process.wait()
+    if return_code != 0:
+        raise subprocess.CalledProcessError(return_code, list(command))
+
+
+def _print_report(report: dict[str, object]) -> None:
+    rows = report["rows"]
+    assert isinstance(rows, list)
+    print("\nPer-iteration timing (ms):")
+    print(f"{'step':>8} {'learner':>12} {'collector':>12} {'iter':>12} {'reward':>12}")
+    for row in rows:
+        assert isinstance(row, dict)
+        reward = row.get("reward")
+        reward_text = f"{float(reward):12.4f}" if reward is not None else f"{'-':>12}"
+        iter_time = row.get("iter_ms")
+        iter_text = f"{float(iter_time):12.3f}" if iter_time is not None else f"{'-':>12}"
+        print(
+            f"{int(row['step']):8d} {float(row['learner_train_ms']):12.3f} "
+            f"{float(row['collector_cycle_ms']):12.3f} {iter_text} {reward_text}"
+        )
+    print("\nSummary (ms):")
+    print(f"{'phase':<18} {'mean':>10} {'median':>10} {'p90':>10} {'p95':>10} {'n':>6}")
+    for name in ("learner_train_ms", "collector_cycle_ms", "iter_ms"):
+        stats = report[name]
+        assert isinstance(stats, dict)
+        print(
+            f"{name:<18} {float(stats['mean_ms']):10.3f} {float(stats['median_ms']):10.3f} "
+            f"{float(stats['p90_ms']):10.3f} {float(stats['p95_ms']):10.3f} {int(stats['count']):6d}"
+        )
+
+
+def parse_args(argv: Sequence[str] | None = None) -> argparse.Namespace:
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("--backend", choices=("mujoco", "motrix"), default="mujoco")
+    parser.add_argument("--task", default="g1_walk_flat")
+    parser.add_argument("--iterations", type=int, default=20)
+    parser.add_argument("--num-envs", type=int, default=256)
+    parser.add_argument("--batch-size", type=int, default=256)
+    parser.add_argument("--replay-buffer-n", type=int, default=32)
+    parser.add_argument("--learning-starts", type=int, default=8)
+    parser.add_argument("--updates-per-step", type=int, default=2)
+    parser.add_argument("--compile", action=argparse.BooleanOptionalAction, default=True)
+    parser.add_argument("--run-dir", type=Path, default=None)
+    parser.add_argument("--output", type=Path, default=None)
+    parser.add_argument("--keep-run", action="store_true")
+    parser.add_argument(
+        "--skip-first",
+        type=int,
+        default=0,
+        help="Exclude the first N common timing rows from summary statistics (compile warm-up).",
+    )
+    parser.add_argument("--uni-rl-src", type=Path, default=None)
+    parser.add_argument("--extra-override", action="append", default=[])
+    return parser.parse_args(argv)
+
+
+def main(argv: Sequence[str] | None = None) -> int:
+    args = parse_args(argv)
+    if args.run_dir is None:
+        run_dir = DEFAULT_OUTPUT_ROOT / datetime.now().strftime("%Y%m%d_%H%M%S")
+    else:
+        run_dir = args.run_dir.resolve()
+    run_dir.mkdir(parents=True, exist_ok=True)
+    env = os.environ.copy()
+    source_paths = [str(ROOT_DIR / "src")]
+    if args.uni_rl_src is not None:
+        source_paths.insert(0, str(args.uni_rl_src.resolve()))
+    elif (ROOT_DIR.parent / "unilab_rl-flashsac-optimization" / "src").is_dir():
+        source_paths.insert(0, str(ROOT_DIR.parent / "unilab_rl-flashsac-optimization" / "src"))
+    env["PYTHONPATH"] = os.pathsep.join(source_paths + [env.get("PYTHONPATH", "")])
+    command = _command(args, run_dir)
+    _run(command, env=env)
+    report = parse_timing(run_dir, skip_first=args.skip_first)
+    payload = {
+        "command": command,
+        "run_dir": str(run_dir),
+        "backend": args.backend,
+        "task": args.task,
+        "device": get_device_info_dict(),
+        **report,
+    }
+    _print_report(report)
+    if args.output is not None:
+        args.output.parent.mkdir(parents=True, exist_ok=True)
+        args.output.write_text(json.dumps(payload, indent=2) + "\n", encoding="utf-8")
+        print(f"\nSaved JSON: {args.output}")
+    if not args.keep_run and args.output is None:
+        # Keep the run by default when --output is requested; otherwise leave
+        # it available for TensorBoard inspection because it contains the
+        # actual physics-backed training artifacts.
+        print(f"Training logs: {run_dir}")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/src/unilab/base/np_env.py b/src/unilab/base/np_env.py
index 5b3022aeb..1f9cadccf 100644
--- a/src/unilab/base/np_env.py
+++ b/src/unilab/base/np_env.py
@@ -614,7 +614,12 @@ def play_capabilities(self) -> EnvPlayCapabilities:
             supports_native_video_capture=capabilities.supports_native_video_capture,
             supports_debug_overlay=capabilities.supports_debug_overlay,
             supports_interactive_debug_overlay=capabilities.supports_interactive_debug_overlay,
-            supports_mocap_playback=capabilities.supports_mocap_playback,
+            # Older unisim-core releases do not expose mocap playback on the
+            # backend capability record.  Keep the env contract fail-closed so
+            # collectors can still run against those physics adapters.
+            supports_mocap_playback=bool(
+                getattr(capabilities, "supports_mocap_playback", False)
+            ),
         )
 
     def get_playback_model(self, env_index: int | None = None) -> Any:
diff --git a/src/unilab/conf/flashsac/config.yaml b/src/unilab/conf/flashsac/config.yaml
index a7ee005fb..1cf560698 100644
--- a/src/unilab/conf/flashsac/config.yaml
+++ b/src/unilab/conf/flashsac/config.yaml
@@ -46,6 +46,13 @@ algo:
     amp_dtype: auto
     use_compile: true
     compile_full_objectives: true
+    # Optional manual graph paths retained for compatibility with the
+    # optimized unilab-rl FlashSAC builder.  Full-objective compile is the
+    # default; these are disabled unless explicitly benchmarked.
+    use_cuda_graph_critic: false
+    use_cuda_graph_actor: false
+    use_cuda_graph_critic_packed_staging: false
+    use_cuda_graph_actor_packed_staging: false
 
 training:
   task_name: G1WalkFlat