diff --git a/AGENTS.md b/AGENTS.md
index a8421e7..b71b642 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,7 +1,5 @@
 ## 设计约束
 
-复杂的对象 都使用 D:\ae\proj\Aethera\kernel\src\kernel\double_buffer\model.hpp 并且使用其提供的线程模型
-
 ``
 除非特别说明不允许写任何同步等待代码。
 除非特别说明不允许写任何同步等待代码。
diff --git a/kernel/kernel/include/frame_policy/design.md b/kernel/kernel/include/frame_policy/design.md
deleted file mode 100644
index fb9128d..0000000
--- a/kernel/kernel/include/frame_policy/design.md
+++ /dev/null
@@ -1,388 +0,0 @@
-有了：
-
-```cpp
-schedule_after(...)
-schedule_every(...)
-reschedule(...)
-```
-
-你这个异步图表库的帧策略就很好做了。我觉得至少有 5 种值得保留，而且可以统一到同一套 `Frame_Policy` 上。
-
-### 1. 固定帧率 + latest-only
-
-最适合动画、交互拖动、持续变化场景。
-
-```cpp
-timer = timers.schedule_every(16.666ms, [this] {
-    request_render();
-});
-```
-
-比如 60 FPS：
-
-```text
-Producer:
-状态一直更新
-1 2 3 4 5 6 7 8 9 ...
-
-Timer:
-|----16.67----|----16.67----|----16.67----|
-
-Render:
-     latest         latest         latest
-```
-
-每个 tick：
-
-```cpp
-void on_frame_tick()
-{
-    if(rendering) {
-        return;
-    }
-    if(!dirty) {
-        return;
-    }
-    start_render();
-}
-```
-
-特点是：
-
-```text
-帧率稳定
-不会积压
-旧状态直接被覆盖
-render 慢了就掉帧
-不会延迟越来越大
-```
-
-这个应该是你的 **默认实时模式**。
-
----
-
-### 2. 变化立即渲染 + 最大 FPS 限制
-
-这个我觉得特别适合普通图表。
-
-例如最大 120 FPS：
-
-```text
-状态变化
-   ↓
-如果距离上一帧已经 > 8.33ms
-   ↓
-立即 render
-
-否则
-   ↓
-schedule_after(剩余时间)
-```
-
-逻辑大概：
-
-```cpp
-void request_render()
-{
-    dirty = true;
-
-    if(rendering || frame_pending) {
-        return;
-    }
-
-    auto now = Clock::now();
-    auto elapsed = now - last_render;
-
-    if(elapsed >= min_frame_interval) {
-        start_render();
-    } else {
-        frame_pending = true;
-        frame_timer = timers.schedule_after(
-            min_frame_interval - elapsed,
-            [this] {
-                frame_pending = false;
-                if(dirty && !rendering) {
-                    start_render();
-                }
-            }
-        );
-    }
-}
-```
-
-比如用户只偶尔：
-
-```text
-set_data()
-```
-
-不会傻等下一个固定 16.67ms tick，而是：
-
-```text
-空闲很久
- ↓
-set_data
- ↓
-立即渲染
-```
-
-如果疯狂变化：
-
-```text
-set_data set_data set_data set_data...
-```
-
-又自动被限制在：
-
-```text
-≤ 120 FPS
-```
-
-这个兼顾：
-
-**低延迟 + 限制资源占用。**
-
-我认为这个非常适合做你的默认 `Auto` 模式。
-
----
-
-### 3. Debounce 静止后渲染
-
-直接发挥 `reschedule()` 的优势。
-
-例如：
-
-```cpp
-void on_change()
-{
-    dirty = true;
-    timers.reschedule(render_timer, 20ms);
-}
-```
-
-连续变化：
-
-```text
-change
-    ↓20ms
-change
-    ↓20ms
-change
-    ↓20ms
-change
-    ↓20ms
-最终静止
-    ↓20ms
-render
-```
-
-适合：
-
-```text
-窗口 resize
-大批量属性连续设置
-布局参数连续修改
-一次 transaction 内多次 set_xxx()
-```
-
-但不适合鼠标拖动这种要求实时视觉反馈的场景，因为它可能一直不渲染。
-
-所以它应该叫类似：
-
-```cpp
-Frame_Mode::Debounce
-```
-
-而不是普通实时模式。
-
----
-
-### 4. 立即首帧 + 后续合并
-
-这个对于 UI/图表体验很好。
-
-第一次变化：
-
-```text
-change
- ↓
-立即 render
-```
-
-紧接着的大量变化：
-
-```text
-change change change change
-              ↓
-         合并一段时间
-              ↓
-         render latest
-```
-
-例如：
-
-```cpp
-void request_render()
-{
-    dirty = true;
-
-    if(!cooldown) {
-        start_render();
-
-        cooldown = true;
-        timer = timers.schedule_after(16ms, [this] {
-            cooldown = false;
-
-            if(dirty) {
-                request_render();
-            }
-        });
-    }
-}
-```
-
-效果：
-
-```text
-事件      X XXXXXXXX XXXXXX
-渲染      R--------R--------R
-```
-
-第一帧延迟非常低，同时限制后面帧率。
-
-这种经常比纯：
-
-```cpp
-schedule_every(16ms)
-```
-
-用户体验更好，因为不会出现“刚好错过 tick，要额外等 16ms”。
-
----
-
-### 5. 动态帧率 / Adaptive
-
-这是最终可以做得很漂亮的一种。
-
-比如：
-
-```text
-有动画 / 拖动       → 120 FPS
-普通数据变化        → 60 FPS
-几秒没变化          → 不跑 timer
-后台低优先级刷新    → 10 FPS
-```
-
-状态机：
-
-```text
-Idle
- │
- │ change
- ▼
-Interactive
- 120 FPS
- │
- │ 一段时间无高频输入
- ▼
-Normal
- 60 FPS
- │
- │ 长时间不变
- ▼
-Idle
- timer取消
-```
-
-这里 `schedule_every` 和 `reschedule` 正好可以配合。
-
-甚至可以根据 render duration 自动降帧：
-
-```cpp
-if(render_time > 16ms) {
-    target_fps = 30;
-} else if(render_time < 6ms) {
-    target_fps = 60;
-}
-```
-
-但这里要加迟滞，不能：
-
-```text
-60 → 30 → 60 → 30
-```
-
-疯狂抖。
-
----
-
-我会给你的库最终留这几个策略：
-
-| 策略        | 行为                     | 适合                     |
-|-------------|--------------------------|--------------------------|
-| `Immediate` | 有变化立即 render        | 截图、离线、低频更新     |
-| `Fixed`     | 固定 tick 取 latest      | 动画、稳定 FPS           |
-| `Throttled` | 立即响应，但限制最大 FPS | **普通交互图表，最推荐** |
-| `Debounce`  | 静止一段时间才 render    | resize、批量修改         |
-| `Adaptive`  | 动态 120/60/30/Idle      | 高级实时模式             |
-
-如果是你的图表库，我会把默认策略设成：
-
-```text
-Throttled + Latest-only
-```
-
-即：
-
-```text
-第一帧尽快
-+
-最大 FPS 限制
-+
-render 期间的新变化只标 dirty
-+
-render 完成直接看 latest
-+
-绝不排 render 队列
-```
-
-这几个性质放在一起非常重要。
-
-最终状态实际上只需要：
-
-```cpp
-bool dirty;
-bool rendering;
-bool frame_pending;
-
-Time_Point last_render;
-Timer_Id frame_timer;
-
-Duration min_frame_interval;
-```
-
-整个核心流程就是：
-
-```text
-任意线程 set_xxx()
-       ↓
-     dirty
-       ↓
- request_render
-       ↓
-┌────────────────────┐
-│ 正在 render？ → 等 │
-│ 未到帧间隔？ → timer│
-│ 否则 → 立即 render │
-└────────────────────┘
-       ↓
-render complete
-       ↓
-dirty?
- ↓   ↓
-yes  no
- ↓
-重新走 request_render
-```
-
-这套特别适合你现在这种 **没有主线程、任意线程调用、异步渲染**的架构。
diff --git a/kernel/kernel/include/function/Scene.hpp b/kernel/kernel/include/function/Scene.hpp
new file mode 100644
index 0000000..2342295
--- /dev/null
+++ b/kernel/kernel/include/function/Scene.hpp
@@ -0,0 +1,2 @@
+#pragma once
+struct Scene {};
diff --git a/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.cpp b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.cpp
new file mode 100644
index 0000000..71e8168
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.cpp
@@ -0,0 +1,287 @@
+#include "Throttled_Latest_Only_State.ipp"
+
+#include <exception>
+#include <utility>
+
+namespace aethera::detail {
+namespace {
+template<typename Function>
+struct Scope_Exit {
+    explicit Scope_Exit(Function function) :
+        function(std::move(function)) {}
+    ~Scope_Exit() noexcept {
+        if (active) {
+            function();
+        }
+    }
+    Scope_Exit(const Scope_Exit&) = delete;
+    Scope_Exit& operator=(const Scope_Exit&) = delete;
+    void release() noexcept {
+        active = false;
+    }
+
+    Function function;  /* 离开当前作用域时执行的异常安全清理。 */
+    bool active{true};  /* release 后不再执行清理。 */
+};
+}
+
+Throttled_Latest_Only_State::Throttled_Latest_Only_State(
+    proxy<FP_Scene> scene,
+    proxy<FP_Sink> sink) :
+    d(std::make_unique<Private>()) {
+    d->scene = std::move(scene);
+    d->sink = std::move(sink);
+}
+
+Throttled_Latest_Only_State::~Throttled_Latest_Only_State() = default;
+
+Start_Throttled_Latest_Only_Result
+Throttled_Latest_Only_State::prepare_start() {
+    {
+        std::lock_guard lock(d->mutex);
+        switch (d->phase) {
+        case Private::Phase::running:
+            return Start_Throttled_Latest_Only_Result::already_running;
+        case Private::Phase::starting:
+            return Start_Throttled_Latest_Only_Result::start_in_progress;
+        case Private::Phase::stopping:
+            return Start_Throttled_Latest_Only_Result::stop_in_progress;
+        case Private::Phase::stopped:
+            break;
+        }
+        if (!d->scene || !d->sink) {
+            return Start_Throttled_Latest_Only_Result::dependency_unavailable;
+        }
+        d->phase = Private::Phase::starting;
+    }
+
+    Scope_Exit rollback([this] {
+        std::lock_guard lock(d->mutex);
+        if (d->phase == Private::Phase::starting) {
+            d->phase = Private::Phase::stopped;
+        }
+    });
+    auto frame = d->scene->create_frame();
+    if (!frame) {
+        return Start_Throttled_Latest_Only_Result::frame_unavailable;
+    }
+
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->phase != Private::Phase::starting || d->frame) {
+            std::terminate();
+        }
+        d->frame = std::move(frame);
+        d->frame_phase = Private::Frame_Phase::idle;
+        d->timer_cancelled = false;
+    }
+    rollback.release();
+    return Start_Throttled_Latest_Only_Result::started;
+}
+
+void Throttled_Latest_Only_State::timer_started(Timer_Id id) {
+    std::lock_guard lock(d->mutex);
+    if (id == 0 ||
+        d->phase != Private::Phase::starting ||
+        !d->frame ||
+        d->timer_id.has_value()) {
+        std::terminate();
+    }
+    d->timer_id = id;
+    d->phase = Private::Phase::running;
+}
+
+void Throttled_Latest_Only_State::start_failed() {
+    proxy<FP_Frame> retired_frame;
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->phase != Private::Phase::starting || d->timer_id) {
+            std::terminate();
+        }
+        retired_frame = std::move(d->frame);
+        d->frame_phase = Private::Frame_Phase::idle;
+        d->phase = Private::Phase::stopped;
+    }
+    retired_frame.reset();
+}
+
+Stop_Throttled_Latest_Only_Request
+Throttled_Latest_Only_State::request_stop(
+    Throttled_Latest_Only_Stop_Completion completion) {
+    if (!completion) {
+        return {
+            Stop_Throttled_Latest_Only_Result::completion_missing,
+            std::nullopt};
+    }
+
+    std::lock_guard lock(d->mutex);
+    switch (d->phase) {
+    case Private::Phase::stopped:
+        return {
+            Stop_Throttled_Latest_Only_Result::already_stopped,
+            std::nullopt};
+    case Private::Phase::starting:
+        return {
+            Stop_Throttled_Latest_Only_Result::start_in_progress,
+            std::nullopt};
+    case Private::Phase::stopping:
+        return {
+            Stop_Throttled_Latest_Only_Result::already_stopping,
+            std::nullopt};
+    case Private::Phase::running:
+        break;
+    }
+    if (!d->timer_id) {
+        std::terminate();
+    }
+    d->phase = Private::Phase::stopping;
+    d->stop_completion = std::move(completion);
+    d->timer_cancelled = false;
+    return {
+        Stop_Throttled_Latest_Only_Result::stopping,
+        d->timer_id};
+}
+
+void Throttled_Latest_Only_State::cancel_failed() {
+    std::lock_guard lock(d->mutex);
+    if (d->phase != Private::Phase::stopping ||
+        d->timer_cancelled) {
+        std::terminate();
+    }
+    d->stop_completion = {};
+    d->phase = Private::Phase::running;
+}
+
+void Throttled_Latest_Only_State::timer_cancelled() {
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->phase != Private::Phase::stopping ||
+            d->timer_cancelled) {
+            std::terminate();
+        }
+        d->timer_id.reset();
+        d->timer_cancelled = true;
+    }
+    finish_stop_if_ready();
+}
+
+void Throttled_Latest_Only_State::frame_due() {
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->phase != Private::Phase::running ||
+            d->frame_phase != Private::Frame_Phase::idle) {
+            return;
+        }
+        d->frame_phase = Private::Frame_Phase::rendering;
+    }
+
+    auto self = shared_from_this();
+    try {
+        d->scene->render(
+            d->frame,
+            [self = std::move(self)](proxy<FP_Frame>& frame) {
+                self->rendered(frame);
+            });
+    }
+    catch (...) {
+        abandon_render();
+        throw;
+    }
+}
+
+void Throttled_Latest_Only_State::rendered(
+    proxy<FP_Frame>& completed_frame) {
+    {
+        std::lock_guard lock(d->mutex);
+        if (std::addressof(completed_frame) !=
+                std::addressof(d->frame) ||
+            d->frame_phase != Private::Frame_Phase::rendering) {
+            std::terminate();
+        }
+        d->frame_phase = Private::Frame_Phase::sending;
+    }
+
+    auto self = shared_from_this();
+    try {
+        d->sink->send(
+            d->frame,
+            [self = std::move(self)](proxy<FP_Frame>& frame) {
+                self->sent(frame);
+            });
+    }
+    catch (...) {
+        abandon_send();
+        throw;
+    }
+}
+
+void Throttled_Latest_Only_State::sent(
+    proxy<FP_Frame>& completed_frame) {
+    {
+        std::lock_guard lock(d->mutex);
+        if (std::addressof(completed_frame) !=
+                std::addressof(d->frame) ||
+            d->frame_phase != Private::Frame_Phase::sending) {
+            std::terminate();
+        }
+        d->frame_phase = Private::Frame_Phase::idle;
+    }
+    finish_stop_if_ready();
+}
+
+void Throttled_Latest_Only_State::abandon_render() {
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->frame_phase != Private::Frame_Phase::rendering) {
+            return;
+        }
+        d->frame_phase = Private::Frame_Phase::idle;
+    }
+    finish_stop_if_ready();
+}
+
+void Throttled_Latest_Only_State::abandon_send() {
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->frame_phase != Private::Frame_Phase::sending) {
+            return;
+        }
+        d->frame_phase = Private::Frame_Phase::idle;
+    }
+    finish_stop_if_ready();
+}
+
+void Throttled_Latest_Only_State::finish_stop_if_ready() {
+    proxy<FP_Frame> retired_frame;
+    Throttled_Latest_Only_Stop_Completion completion;
+    {
+        std::lock_guard lock(d->mutex);
+        if (d->phase != Private::Phase::stopping ||
+            !d->timer_cancelled ||
+            d->frame_phase != Private::Frame_Phase::idle) {
+            return;
+        }
+        retired_frame = std::move(d->frame);
+        completion = std::move(d->stop_completion);
+        d->timer_cancelled = false;
+        d->phase = Private::Phase::stopped;
+    }
+
+    retired_frame.reset();
+    try {
+        completion();
+    }
+    catch (...) {
+        std::terminate();
+    }
+}
+
+bool Throttled_Latest_Only_State::destructible() const noexcept {
+    std::lock_guard lock(d->mutex);
+    return d->phase == Private::Phase::stopped &&
+        d->frame_phase == Private::Frame_Phase::idle &&
+        !d->frame &&
+        !d->timer_id &&
+        !d->stop_completion;
+}
+}
diff --git a/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.hpp b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.hpp
new file mode 100644
index 0000000..58b054b
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include "function/frame_policy/global.hpp"
+#include "time_thread/Timer_Service.hpp"
+
+#include <memory>
+#include <optional>
+
+namespace aethera::detail {
+struct Stop_Throttled_Latest_Only_Request {
+    Stop_Throttled_Latest_Only_Result result; /* 本次停止请求的已知结果。 */
+    std::optional<Timer_Id> timer_id;         /* stopping 时必须异步取消的计时器。 */
+};
+
+struct Throttled_Latest_Only_State :
+    Non_Copyable,
+    std::enable_shared_from_this<Throttled_Latest_Only_State> {
+    Throttled_Latest_Only_State(proxy<FP_Scene> scene,
+                                proxy<FP_Sink> sink);
+    ~Throttled_Latest_Only_State();
+
+    Start_Throttled_Latest_Only_Result prepare_start();
+    void timer_started(Timer_Id id);
+    void start_failed();
+    Stop_Throttled_Latest_Only_Request request_stop(
+        Throttled_Latest_Only_Stop_Completion completion);
+    void cancel_failed();
+    void timer_cancelled();
+    void frame_due();
+    [[nodiscard]] bool destructible() const noexcept;
+private:
+    struct Private;
+    void rendered(proxy<FP_Frame>& completed_frame);
+    void sent(proxy<FP_Frame>& completed_frame);
+    void abandon_render();
+    void abandon_send();
+    void finish_stop_if_ready();
+    std::unique_ptr<Private> d;
+};
+}
diff --git a/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.ipp b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.ipp
new file mode 100644
index 0000000..b6e7968
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/detail/Throttled_Latest_Only_State.ipp
@@ -0,0 +1,31 @@
+#pragma once
+
+#include "Throttled_Latest_Only_State.hpp"
+
+#include <mutex>
+
+namespace aethera::detail {
+struct Throttled_Latest_Only_State::Private {
+    enum struct Phase : std::uint8_t {
+        stopped,
+        starting,
+        running,
+        stopping
+    };
+    enum struct Frame_Phase : std::uint8_t {
+        idle,
+        rendering,
+        sending
+    };
+
+    proxy<FP_Scene> scene;                              /* 帧类型和渲染借用的业务实现所有权。 */
+    proxy<FP_Sink> sink;                                /* 当前帧媒体分派的业务实现所有权。 */
+    proxy<FP_Frame> frame;                              /* 策略创建、复用并在停止完成前销毁的唯一帧。 */
+    Throttled_Latest_Only_Stop_Completion stop_completion; /* 本次异步停止的唯一完成回调。 */
+    std::optional<Timer_Id> timer_id;                   /* running/stopping 阶段的周期计时器标识。 */
+    mutable std::mutex mutex;                           /* 保护生命周期和跨线程帧借用阶段。 */
+    Phase phase{Phase::stopped};                        /* start/stop 生命周期的唯一权威状态。 */
+    Frame_Phase frame_phase{Frame_Phase::idle};         /* 唯一帧当前借用方的权威状态。 */
+    bool timer_cancelled{};                             /* stopping 阶段的异步取消确认。 */
+};
+}
diff --git a/kernel/kernel/include/function/frame_policy/global.cpp b/kernel/kernel/include/function/frame_policy/global.cpp
new file mode 100644
index 0000000..7d5c318
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/global.cpp
@@ -0,0 +1,87 @@
+#include "global.ipp"
+
+#include "time_thread/Timer_Service.hpp"
+
+#include <exception>
+#include <utility>
+
+namespace aethera {
+Throttled_Latest_only::Private::Private(
+    proxy<FP_Scene> scene,
+    proxy<FP_Sink> sink) :
+    state(std::make_shared<detail::Throttled_Latest_Only_State>(
+        std::move(scene),
+        std::move(sink))) {}
+
+Throttled_Latest_only::Throttled_Latest_only(
+    proxy<FP_Scene> scene,
+    proxy<FP_Sink> sink) :
+    d(std::make_unique<Private>(std::move(scene), std::move(sink))) {}
+
+Throttled_Latest_only::~Throttled_Latest_only() noexcept {
+    if (!d->state->destructible()) {
+        std::terminate();
+    }
+}
+
+Start_Throttled_Latest_Only_Result
+Throttled_Latest_only::start(double frames_per_second) {
+    const auto interval =
+        detail::timer_interval_from_frames_per_second(frames_per_second);
+    if (!interval) {
+        return interval.error() ==
+                Schedule_Every_Fps_Result::invalid_frames_per_second
+            ? Start_Throttled_Latest_Only_Result::invalid_frames_per_second
+            : Start_Throttled_Latest_Only_Result::interval_out_of_range;
+    }
+
+    const auto prepared = d->state->prepare_start();
+    if (prepared != Start_Throttled_Latest_Only_Result::started) {
+        return prepared;
+    }
+
+    const auto state = d->state;
+    Timer_Id timer_id{};
+    try {
+        timer_id =
+            Timer_Service::instance().schedule_every(
+                *interval,
+                [state] {
+                    state->frame_due();
+                });
+    }
+    catch (...) {
+        state->start_failed();
+        throw;
+    }
+    state->timer_started(timer_id);
+    return Start_Throttled_Latest_Only_Result::started;
+}
+
+Stop_Throttled_Latest_Only_Result
+Throttled_Latest_only::stop(
+    Throttled_Latest_Only_Stop_Completion completion) {
+    auto request = d->state->request_stop(std::move(completion));
+    if (request.result !=
+        Stop_Throttled_Latest_Only_Result::stopping) {
+        return request.result;
+    }
+    if (!request.timer_id) {
+        std::terminate();
+    }
+
+    try {
+        const auto state = d->state;
+        Timer_Service::instance().cancel(
+            *request.timer_id,
+            [state] {
+                state->timer_cancelled();
+            });
+    }
+    catch (...) {
+        d->state->cancel_failed();
+        throw;
+    }
+    return Stop_Throttled_Latest_Only_Result::stopping;
+}
+}
diff --git a/kernel/kernel/include/function/frame_policy/global.hpp b/kernel/kernel/include/function/frame_policy/global.hpp
new file mode 100644
index 0000000..fd2011d
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/global.hpp
@@ -0,0 +1,60 @@
+#pragma once
+#include "../../global.hpp"
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <proxy/proxy.h>
+namespace aethera {
+using Time_Type = std::uint64_t;
+PRO_DEF_MEM_DISPATCH(FP_Frame_use_time, use_time);
+struct FP_Frame : facade_builder
+::add_convention<FP_Frame_use_time, Time_Type()>
+::build {};
+using FP_Frame_Completion =
+std::function<void(proxy<FP_Frame>&)>;
+PRO_DEF_MEM_DISPATCH(FP_create_frame, create_frame);
+PRO_DEF_MEM_DISPATCH(FP_render, render);
+struct FP_Scene : facade_builder
+::add_convention<FP_create_frame, proxy<FP_Frame>()>
+::add_convention<FP_render, void(proxy<FP_Frame>&, FP_Frame_Completion)>
+::build {};
+PRO_DEF_MEM_DISPATCH(FP_send, send);
+struct FP_Sink : facade_builder
+::add_convention<FP_send, void(proxy<FP_Frame>&, FP_Frame_Completion)>
+::build {};
+enum struct Start_Throttled_Latest_Only_Result : std::uint8_t {
+    started,
+    already_running,
+    start_in_progress,
+    stop_in_progress,
+    dependency_unavailable,
+    frame_unavailable,
+    invalid_frames_per_second,
+    interval_out_of_range
+};
+enum struct Stop_Throttled_Latest_Only_Result : std::uint8_t {
+    stopping,
+    already_stopped,
+    already_stopping,
+    start_in_progress,
+    completion_missing
+};
+using Throttled_Latest_Only_Stop_Completion =
+std::function<void()>;
+/*
+ * 固定帧率、最多一帧在途的策略。Scene 创建具体帧；策略持有并重复使用，
+ * stop completion 执行前会排空 Scene/Sink 借用并销毁该帧。
+ */
+struct Throttled_Latest_only : Immovable {
+    Throttled_Latest_only(proxy<FP_Scene> scene,
+                          proxy<FP_Sink> sink);
+    ~Throttled_Latest_only() noexcept;
+    Start_Throttled_Latest_Only_Result start(
+        double frames_per_second);
+    Stop_Throttled_Latest_Only_Result stop(
+        Throttled_Latest_Only_Stop_Completion completion);
+private:
+    struct Private;
+    std::unique_ptr<Private> d; /* 策略外壳实现的唯一所有权。 */
+};
+}
diff --git a/kernel/kernel/include/function/frame_policy/global.ipp b/kernel/kernel/include/function/frame_policy/global.ipp
new file mode 100644
index 0000000..c4247cc
--- /dev/null
+++ b/kernel/kernel/include/function/frame_policy/global.ipp
@@ -0,0 +1,13 @@
+#pragma once
+
+#include "global.hpp"
+#include "detail/Throttled_Latest_Only_State.hpp"
+
+namespace aethera {
+struct Throttled_Latest_only::Private {
+    Private(proxy<FP_Scene> scene,
+            proxy<FP_Sink> sink);
+
+    std::shared_ptr<detail::Throttled_Latest_Only_State> state; /* 帧、借用阶段和停止排空的共享所有权。 */
+};
+}
diff --git a/kernel/kernel/include/function/renderable.hpp b/kernel/kernel/include/function/renderable.hpp
new file mode 100644
index 0000000..6f70f09
--- /dev/null
+++ b/kernel/kernel/include/function/renderable.hpp
@@ -0,0 +1 @@
+#pragma once
diff --git a/kernel/kernel/include/global.hpp b/kernel/kernel/include/global.hpp
index d339d29..7b8141a 100644
--- a/kernel/kernel/include/global.hpp
+++ b/kernel/kernel/include/global.hpp
@@ -7,7 +7,10 @@
 #include <thread>
 #include <type_traits>
 #include <utility>
+#include "proxy/v4/detail/facade_creation.h"
 namespace aethera {
+using pro::facade_builder;
+using pro::proxy;
 struct Non_Copyable {
 protected:
     Non_Copyable() = default;
diff --git a/kernel/kernel/include/task_flow/Task_Graph.cpp b/kernel/kernel/include/task_flow/Task_Graph.cpp
index d448525..b52dcb4 100644
--- a/kernel/kernel/include/task_flow/Task_Graph.cpp
+++ b/kernel/kernel/include/task_flow/Task_Graph.cpp
@@ -1,5 +1,5 @@
 #include "Task_Graph.hpp"
-#include "Task_Graph_Execution.hpp"
+#include "detail/Taskflow_Execution.ipp"
 #include <algorithm>
 #include <atomic>
 #include <exception>
diff --git a/kernel/kernel/include/task_flow/Task_Graph_Execution.hpp b/kernel/kernel/include/task_flow/Task_Graph_Execution.hpp
deleted file mode 100644
index 93dcd10..0000000
--- a/kernel/kernel/include/task_flow/Task_Graph_Execution.hpp
+++ /dev/null
@@ -1,33 +0,0 @@
-#pragma once
-#include "Task_Graph.hpp"
-#include "Taskflow_Trace.hpp"
-#include <exception>
-#include <functional>
-#include <memory>
-#include <vector>
-namespace tf {
-class Taskflow;
-}
-namespace aethera::detail {
-/* 一次异步执行对根图及全部子图的独占租约。 */
-struct Task_Graph_Execution final {
-private:
-    struct Construction_Key {};
-public:
-    static std::shared_ptr<Task_Graph_Execution> try_acquire(
-        Task_Graph& graph);
-    ~Task_Graph_Execution();
-    Task_Graph_Execution(const Task_Graph_Execution&) = delete;
-    Task_Graph_Execution(Task_Graph_Execution&&) = delete;
-    Task_Graph_Execution& operator=(const Task_Graph_Execution&) = delete;
-    Task_Graph_Execution& operator=(Task_Graph_Execution&&) = delete;
-    explicit Task_Graph_Execution(Construction_Key);
-    tf::Taskflow& native_taskflow() noexcept;
-    std::vector<Taskflow_Node_Trace> nodes() const;
-    void bind_observation(void* observation) noexcept;
-    std::exception_ptr take_failure() noexcept;
-private:
-    std::shared_ptr<Task_Graph::Private> root;
-    std::vector<std::reference_wrapper<Task_Graph::Private>> graphs;
-};
-}
diff --git a/kernel/kernel/include/task_flow/Task_Runtime.cpp b/kernel/kernel/include/task_flow/Task_Runtime.cpp
index e7e9ee6..076d5bd 100644
--- a/kernel/kernel/include/task_flow/Task_Runtime.cpp
+++ b/kernel/kernel/include/task_flow/Task_Runtime.cpp
@@ -1,9 +1,9 @@
 #include "Task_Runtime.hpp"
-#include "Task_Graph_Execution.hpp"
-#include "Taskflow_Observation_Execution.hpp"
+#include "detail/Taskflow_Execution.ipp"
 #include <atomic>
 #include <chrono>
 #include <memory>
+#include <optional>
 #include <string>
 #include <taskflow/observer/interface.hpp>
 #include <taskflow/taskflow.hpp>
@@ -98,24 +98,31 @@ public:
     Run_Taskflow_Result run(
         Task_Graph& graph,
         Taskflow_Completion completion,
-        Taskflow_Observation observation) {
+        std::optional<Taskflow_Observation> observation) {
         if (!ready()) return Run_Taskflow_Result::runtime_not_initialized;
         if (!completion) return Run_Taskflow_Result::completion_missing;
         auto graph_execution = detail::Task_Graph_Execution::try_acquire(graph);
         if (!graph_execution) return Run_Taskflow_Result::graph_busy;
         std::string taskflow_name;
         std::vector<Taskflow_Node_Trace> nodes;
-        if (detail::Taskflow_Observation_Execution::requested(observation)) {
+        if (observation &&
+            detail::Taskflow_Observation_Execution::requested(*observation)) {
             auto& taskflow = graph_execution->native_taskflow();
             taskflow_name = taskflow.name();
             nodes = graph_execution->nodes();
         }
-        auto observation_execution =
-        detail::Taskflow_Observation_Execution::try_start(
-            std::move(observation),
-            executor->num_workers(),
-            std::move(taskflow_name),
-            std::move(nodes));
+        auto observation_execution = [&]() -> std::expected<
+            detail::Taskflow_Observation_Execution,
+            detail::Start_Taskflow_Observation_Result> {
+            if (!observation) {
+                return detail::Taskflow_Observation_Execution{};
+            }
+            return detail::Taskflow_Observation_Execution::try_start(
+                std::move(*observation),
+                executor->num_workers(),
+                std::move(taskflow_name),
+                std::move(nodes));
+        }();
         if (!observation_execution) {
             return Run_Taskflow_Result::observation_unavailable;
         }
@@ -172,6 +179,14 @@ Initialize_Task_Runtime_Result initialize_task_runtime(
     std::size_t workers) {
     return Task_Resource::instance().initialize(workers);
 }
+Run_Taskflow_Result run_taskflow(
+    Task_Graph& graph,
+    Taskflow_Completion completion) {
+    return Task_Resource::instance().run(
+        graph,
+        std::move(completion),
+        std::nullopt);
+}
 Run_Taskflow_Result run_taskflow(
     Task_Graph& graph,
     Taskflow_Completion completion,
diff --git a/kernel/kernel/include/task_flow/Task_Runtime.hpp b/kernel/kernel/include/task_flow/Task_Runtime.hpp
index 48f3334..e75de1f 100644
--- a/kernel/kernel/include/task_flow/Task_Runtime.hpp
+++ b/kernel/kernel/include/task_flow/Task_Runtime.hpp
@@ -23,9 +23,13 @@ enum struct Run_Taskflow_Result : std::uint8_t {
 using Taskflow_Completion = std::function<void(std::exception_ptr)>;
 Initialize_Task_Runtime_Result initialize_task_runtime(
     std::size_t workers = std::thread::hardware_concurrency());
-/* 完成回调接收业务任务传播出的 Unknown Failure；observation 自身决定是否记录。 */
+/* 完成回调接收业务任务传播出的 Unknown Failure；本次执行不记录观察数据。 */
+Run_Taskflow_Result run_taskflow(
+    Task_Graph& graph,
+    Taskflow_Completion completion);
+/* 完成回调接收业务任务传播出的 Unknown Failure；observation 记录本次执行。 */
 Run_Taskflow_Result run_taskflow(
     Task_Graph& graph,
     Taskflow_Completion completion,
-    Taskflow_Observation observation = Taskflow_Observation{});
+    Taskflow_Observation observation);
 }
diff --git a/kernel/kernel/include/task_flow/Taskflow_Observation.cpp b/kernel/kernel/include/task_flow/Taskflow_Observation.cpp
index 34912fc..800078a 100644
--- a/kernel/kernel/include/task_flow/Taskflow_Observation.cpp
+++ b/kernel/kernel/include/task_flow/Taskflow_Observation.cpp
@@ -1,5 +1,5 @@
 #include "Taskflow_Observation.hpp"
-#include "Taskflow_Observation_Execution.hpp"
+#include "detail/Taskflow_Execution.ipp"
 #include <atomic>
 #include <chrono>
 #include <expected>
@@ -28,7 +28,9 @@ struct Taskflow_Observation::Private {
         std::vector<Start_Record> starts{}; /* 对应 Worker 的嵌套调用栈。 */
         std::size_t ignored_depth{}; /* 栈写入失败后用于配平回调的嵌套深度。 */
     };
-    explicit Private(std::string observation_stage) : stage(std::move(observation_stage)) {}
+    explicit Private(std::string observation_stage) {
+        trace.stage = std::move(observation_stage);
+    }
     ~Private() {
         delete failure.exchange(nullptr, std::memory_order_acq_rel);
     }
@@ -54,20 +56,14 @@ struct Taskflow_Observation::Private {
             failure.exchange(nullptr, std::memory_order_acq_rel)};
         return value ? std::move(*value) : std::exception_ptr{};
     }
-    std::string stage{}; /* requested 阶段尚未移入结果的业务阶段。 */
     std::atomic<Observation_Phase> phase{Observation_Phase::requested}; /* 本次观察从请求到消费的唯一权威状态。 */
     Clock::time_point started_at{}; /* 所有执行相对时间的单调时钟原点。 */
-    Taskflow_Execution_Trace trace{}; /* recording/ready 阶段的唯一记录数据。 */
+    Taskflow_Execution_Trace trace{}; /* requested 阶段保存 stage，随后保存唯一记录数据。 */
     std::vector<Worker_State> worker_states{}; /* 仅在 recording 阶段存在的逐 Worker 单写状态。 */
     std::atomic<std::exception_ptr*> failure{}; /* 原子槽暂存可空所有权；取出后立即由 unique_ptr 接管。 */
 };
-Taskflow_Observation::Taskflow_Observation(
-    Taskflow_Observation_Mode mode,
-    std::string stage) {
-    if (mode == Taskflow_Observation_Mode::record) {
-        d = std::make_shared<Private>(std::move(stage));
-    }
-}
+Taskflow_Observation::Taskflow_Observation(std::string stage) :
+    d(std::make_shared<Private>(std::move(stage))) {}
 Taskflow_Observation::~Taskflow_Observation() = default;
 Taskflow_Observation::Taskflow_Observation(const Taskflow_Observation&) = default;
 Taskflow_Observation::Taskflow_Observation(Taskflow_Observation&&) noexcept = default;
@@ -123,7 +119,8 @@ std::expected<detail::Taskflow_Observation_Execution,
     std::string taskflow_name,
     std::vector<Taskflow_Node_Trace> nodes) {
     if (!observation.d) {
-        return Taskflow_Observation_Execution{std::move(observation)};
+        return std::unexpected{
+            Start_Taskflow_Observation_Result::unavailable};
     }
     auto phase = observation.d->phase.load(std::memory_order_acquire);
     if (phase != Observation_Phase::requested ||
@@ -140,6 +137,7 @@ std::expected<detail::Taskflow_Observation_Execution,
         data.started_at = Clock::now();
         const auto system_now = std::chrono::system_clock::now().time_since_epoch();
         Taskflow_Execution_Trace trace{};
+        trace.stage = data.trace.stage;
         trace.taskflow_name = std::move(taskflow_name);
         trace.started_time_unix_ns = static_cast<std::uint64_t>(
             std::chrono::duration_cast<std::chrono::nanoseconds>(system_now)
@@ -151,7 +149,6 @@ std::expected<detail::Taskflow_Observation_Execution,
             trace.worker_tasks[worker].reserve(64);
             data.worker_states[worker].starts.reserve(32);
         }
-        trace.stage = std::move(data.stage);
         data.trace = std::move(trace);
     }
     catch (...) {
@@ -161,17 +158,19 @@ std::expected<detail::Taskflow_Observation_Execution,
             std::memory_order_release);
         throw;
     }
-    return Taskflow_Observation_Execution{std::move(observation)};
+    return Taskflow_Observation_Execution{std::move(observation.d)};
 }
 detail::Taskflow_Observation_Execution::Taskflow_Observation_Execution(
-    Taskflow_Observation value) noexcept : observation(std::move(value)) {}
+    std::shared_ptr<Taskflow_Observation::Private> value) noexcept :
+    observation(std::move(value)) {}
+detail::Taskflow_Observation_Execution::Taskflow_Observation_Execution() noexcept = default;
 detail::Taskflow_Observation_Execution::~Taskflow_Observation_Execution() {
     cancel();
 }
 detail::Taskflow_Observation_Execution::Taskflow_Observation_Execution(
     Taskflow_Observation_Execution&&) noexcept = default;
 void* detail::Taskflow_Observation_Execution::binding() noexcept {
-    return observation.d.get();
+    return observation ? this : nullptr;
 }
 void detail::Taskflow_Observation_Execution::observe_entry(
     std::size_t worker,
@@ -179,7 +178,7 @@ void detail::Taskflow_Observation_Execution::observe_entry(
     std::size_t queue_size,
     std::size_t queue_capacity,
     Clock::time_point entered) noexcept {
-    auto& data = *observation.d;
+    auto& data = *observation;
     if (worker >= data.worker_states.size()) std::terminate();
     auto& state = data.worker_states[worker];
     if (state.ignored_depth != 0) {
@@ -204,7 +203,7 @@ void detail::Taskflow_Observation_Execution::observe_exit(
     std::size_t worker,
     std::uint64_t native_id,
     Clock::time_point finished) noexcept {
-    auto& data = *observation.d;
+    auto& data = *observation;
     if (worker >= data.worker_states.size()) std::terminate();
     auto& state = data.worker_states[worker];
     if (state.ignored_depth != 0) {
@@ -234,23 +233,24 @@ void detail::Taskflow_Observation_Execution::observe_exit(
 }
 void detail::Taskflow_Observation_Execution::finish(
     Clock::time_point executor_finished) noexcept {
-    if (!observation.d) return;
-    auto& data = *observation.d;
+    if (!observation) return;
+    auto& data = *observation;
     data.trace.executor_finished_ms = data.elapsed_ms(executor_finished);
     data.trace.observation_finished_ms = data.elapsed_ms(Clock::now());
     data.phase.store(Observation_Phase::ready, std::memory_order_release);
 }
 void detail::Taskflow_Observation_Execution::cancel() noexcept {
-    if (!observation.d ||
-        observation.d->phase.load(std::memory_order_acquire) !=
+    if (!observation ||
+        observation->phase.load(std::memory_order_acquire) !=
         Observation_Phase::recording) {
         return;
     }
-    auto& data = *observation.d;
+    auto& data = *observation;
     delete data.failure.exchange(nullptr, std::memory_order_acq_rel);
     data.worker_states.clear();
-    data.stage = std::move(data.trace.stage);
+    auto stage = std::move(data.trace.stage);
     data.trace = {};
+    data.trace.stage = std::move(stage);
     data.phase.store(Observation_Phase::requested, std::memory_order_release);
 }
 }
diff --git a/kernel/kernel/include/task_flow/Taskflow_Observation.hpp b/kernel/kernel/include/task_flow/Taskflow_Observation.hpp
index 645abd1..cbb980d 100644
--- a/kernel/kernel/include/task_flow/Taskflow_Observation.hpp
+++ b/kernel/kernel/include/task_flow/Taskflow_Observation.hpp
@@ -4,29 +4,22 @@
 #include <expected>
 #include <memory>
 #include <string>
-#include "../global.hpp"
 namespace aethera {
 namespace detail {
 struct Taskflow_Observation_Execution;
 }
-enum struct Taskflow_Observation_Mode : std::uint8_t {
-    disabled,
-    record
-};
 enum struct Take_Taskflow_Observation_Result : std::uint8_t {
     not_recorded,
     recording,
     already_taken
 };
 /*
- * 一次 Taskflow 执行的可选观察数据。Mode 是是否分配 Worker 记录的唯一来源。
+ * 一次 Taskflow 执行的观察数据。只有把该对象传给 run_taskflow 才会记录。
  * 复制句柄共享同一次观察；执行完成后任一句柄均可取走唯一结果。
  */
 struct Taskflow_Observation {
 public:
-    explicit Taskflow_Observation(
-        Taskflow_Observation_Mode mode = Taskflow_Observation_Mode::disabled,
-        std::string stage = {});
+    explicit Taskflow_Observation(std::string stage);
     ~Taskflow_Observation();
     Taskflow_Observation(const Taskflow_Observation&);
     Taskflow_Observation(Taskflow_Observation&&) noexcept;
diff --git a/kernel/kernel/include/task_flow/design.md b/kernel/kernel/include/task_flow/design.md
index c711555..929ac2b 100644
--- a/kernel/kernel/include/task_flow/design.md
+++ b/kernel/kernel/include/task_flow/design.md
@@ -9,14 +9,14 @@
 | `Task_Graph`                     | 构图、组合子图、保存业务节点元数据             |
 | `Task_Graph_Execution`           | 独占本次执行涉及的根图和子图，并管理运行期借用 |
 | `Task_Runtime`                   | 初始化 Executor、提交执行、传递完成与异常      |
-| `Taskflow_Observation`           | 决定本次执行是否记录，并独占记录状态           |
+| `Taskflow_Observation`           | 表达一次显式记录请求，并独占记录状态           |
 | `Taskflow_Observation_Execution` | 持有本次可选记录；提交失败时自动回滚           |
 | `Taskflow_Execution_Trace`       | 执行完成后移出的原始观察结果                   |
 
 ## 执行流程
 
 1. `run_taskflow` 创建 `Task_Graph_Execution`，独占根图及全部子图；任一图已占用则返回 `graph_busy`。
-2. Observation 为 `record` 时创建逐 Worker 状态，并把其非拥有指针写入所有节点；禁用时不分配记录数据。
+2. 调用方传入 Observation 时创建逐 Worker 状态，并把执行对象的非拥有指针写入所有节点；未传入时不分配记录数据。
 3. 内部执行对象持有 Graph 租约、Observation 执行对象和完成回调，然后提交给 Taskflow。
 4. Observer 从节点读取 Observation 指针；为空立即返回，否则只写 `worker_tasks[worker_id]`。
 5. topology 完成后发布 Observation、清除节点指针、释放 Graph，最后调用业务完成回调。
@@ -24,9 +24,9 @@
 ## 状态与生命周期
 
 - 每张 Graph 的 `active` 是其占用状态的唯一来源；`Task_Graph_Execution` 析构时统一清除借用并释放根图和子图。
-- 禁用 Observation 没有 Private；启用后 `requested → recording → ready → consumed` 是唯一状态链。
+- 未传入 Observation 时没有记录状态；传入后 `requested → recording → ready → consumed` 是唯一状态链。
 - `Taskflow_Execution` 是异步生命周期所有者。调用方可在提交后销毁或移动原 `Task_Graph`/Observation 句柄。
-- 节点中的 `void*` 是可空、非拥有借用；Observation 的共享所有权保证它在最后一次 Observer 回调前有效。
+- 节点中的 `void*` 是指向 Observation 执行对象的可空、非拥有借用；执行所有权保证它在最后一次 Observer 回调前有效。
 - Trace 只保存原始数据。Worker ID 等于 `worker_tasks` 外层下标；后继关系由节点的 `predecessors` 计算。
 
 ## 线程契约
@@ -47,7 +47,6 @@
 
 ```cpp
 Taskflow_Observation observation{
-    Taskflow_Observation_Mode::record,
     "render_2d.frame"};
 
 const auto result = run_taskflow(
diff --git a/kernel/kernel/include/task_flow/Taskflow_Observation_Execution.hpp b/kernel/kernel/include/task_flow/detail/Taskflow_Execution.ipp
similarity index 53%
rename from kernel/kernel/include/task_flow/Taskflow_Observation_Execution.hpp
rename to kernel/kernel/include/task_flow/detail/Taskflow_Execution.ipp
index 70ab6ea..55b3601 100644
--- a/kernel/kernel/include/task_flow/Taskflow_Observation_Execution.hpp
+++ b/kernel/kernel/include/task_flow/detail/Taskflow_Execution.ipp
@@ -1,18 +1,48 @@
 #pragma once
-#include "Taskflow_Observation.hpp"
+#include "../Task_Graph.hpp"
+#include "../Taskflow_Observation.hpp"
+#include "../Taskflow_Trace.hpp"
 #include <chrono>
 #include <cstddef>
 #include <cstdint>
+#include <exception>
 #include <expected>
+#include <functional>
+#include <memory>
 #include <string>
 #include <vector>
+namespace tf {
+class Taskflow;
+}
 namespace aethera::detail {
+/* 一次异步执行对根图及全部子图的独占租约。 */
+struct Task_Graph_Execution final {
+private:
+    struct Construction_Key {};
+public:
+    static std::shared_ptr<Task_Graph_Execution> try_acquire(
+        Task_Graph& graph);
+    ~Task_Graph_Execution();
+    Task_Graph_Execution(const Task_Graph_Execution&) = delete;
+    Task_Graph_Execution(Task_Graph_Execution&&) = delete;
+    Task_Graph_Execution& operator=(const Task_Graph_Execution&) = delete;
+    Task_Graph_Execution& operator=(Task_Graph_Execution&&) = delete;
+    explicit Task_Graph_Execution(Construction_Key);
+    tf::Taskflow& native_taskflow() noexcept;
+    std::vector<Taskflow_Node_Trace> nodes() const;
+    void bind_observation(void* observation) noexcept;
+    std::exception_ptr take_failure() noexcept;
+private:
+    std::shared_ptr<Task_Graph::Private> root;                       /* 根 DAG 的执行期共享所有权。 */
+    std::vector<std::reference_wrapper<Task_Graph::Private>> graphs; /* 本次独占的全部 DAG 非拥有借用。 */
+};
 enum struct Start_Taskflow_Observation_Result : std::uint8_t {
     unavailable
 };
 /* 一次异步执行对 Observation 记录状态的所有权。 */
 struct Taskflow_Observation_Execution final {
 public:
+    Taskflow_Observation_Execution() noexcept;
     static bool requested(
         const Taskflow_Observation& observation) noexcept;
     static std::expected<
@@ -46,8 +76,8 @@ public:
         std::chrono::steady_clock::time_point executor_finished) noexcept;
 private:
     explicit Taskflow_Observation_Execution(
-        Taskflow_Observation observation) noexcept;
+        std::shared_ptr<Taskflow_Observation::Private> observation) noexcept;
     void cancel() noexcept;
-    Taskflow_Observation observation;
+    std::shared_ptr<Taskflow_Observation::Private> observation; /* 可空记录所有权；空表示本次执行未请求观察。 */
 };
 }
diff --git a/kernel/kernel/include/time_thread/Timer_Service.cpp b/kernel/kernel/include/time_thread/Timer_Service.cpp
index 2f75b9d..8d4e06e 100644
--- a/kernel/kernel/include/time_thread/Timer_Service.cpp
+++ b/kernel/kernel/include/time_thread/Timer_Service.cpp
@@ -1,19 +1,25 @@
 #include "Timer_Service.hpp"
-#include "timer-wheel.h"
-#include <algorithm>
+#include "Timer_Time_Source.hpp"
+#include "detail/Timer_Scheduler.hpp"
+
 #include <atomic>
 #include <condition_variable>
 #include <deque>
-#include <limits>
+#include <exception>
 #include <mutex>
 #include <thread>
-#include <unordered_map>
 #include <utility>
-#include <vector>
 namespace aethera {
+namespace {
+struct Steady_Timer_Time_Source final : Timer_Time_Source {
+    Time_Point now() const noexcept override {
+        return std::chrono::steady_clock::now();
+    }
+};
+}
+
 struct Timer_Service::Impl {
-    static constexpr std::chrono::microseconds Tick_Duration{10};
-    static constexpr Tick Max_Wait_Ticks = 100000;
+    static constexpr std::chrono::seconds Maximum_Wait{1};
     enum class Command_Type {
         Add,
         Cancel,
@@ -23,38 +29,17 @@ struct Timer_Service::Impl {
     struct Command {
         Command_Type type;
         Timer_Id id{};
-        Tick delay{};
-        Tick interval{};
+        std::chrono::nanoseconds delay{};
+        std::chrono::nanoseconds interval{};
         Callback callback;
     };
-    struct Event : TimerEventInterface {
-        Impl* owner;
-        Timer_Id id;
-        Tick interval;
-        Callback callback;
-        Event(Impl* owner, Timer_Id id, Tick interval, Callback callback) : owner(owner), id(id), interval(interval), callback(std::move(callback)) {}
-        void execute() override {
-            try {
-                callback();
-            }
-            catch (...) {}
-            if (interval == 0) {
-                owner->completed.emplace_back(id);
-                return;
-            }
-            owner->repeating.emplace_back(id);
-        }
-    };
-    std::unique_ptr<TimerWheel> wheel{std::make_unique<TimerWheel>()};
-    std::unordered_map<Timer_Id, std::unique_ptr<Event>> events;
-    std::vector<Timer_Id> completed;
-    std::vector<Timer_Id> repeating;
+    Steady_Timer_Time_Source time_source;
+    detail::Timer_Scheduler scheduler{time_source};
     std::atomic<Timer_Id> next_id{1};
     std::mutex mutex;
     std::condition_variable cv;
     std::deque<Command> commands;
     std::thread worker;
-    std::chrono::steady_clock::time_point last_update{std::chrono::steady_clock::now()};
     Impl() : worker([this] {
         run();
     }) {}
@@ -62,17 +47,9 @@ struct Timer_Service::Impl {
         push(Command{Command_Type::Stop});
         worker.join();
     }
-    static Tick to_ticks(std::chrono::nanoseconds duration) {
-        if (duration <= std::chrono::nanoseconds::zero()) {
-            return 1;
-        }
-        auto ns = duration.count();
-        auto tick_ns = std::chrono::duration_cast<std::chrono::nanoseconds>(Tick_Duration).count();
-        return static_cast<Tick>((ns + tick_ns - 1) / tick_ns);
-    }
     Timer_Id schedule(std::chrono::nanoseconds delay, std::chrono::nanoseconds interval, Callback callback) {
         Timer_Id id = next_id.fetch_add(1, std::memory_order_relaxed);
-        push(Command{Command_Type::Add, id, to_ticks(delay), interval == std::chrono::nanoseconds::zero() ? 0 : to_ticks(interval), std::move(callback)});
+        push(Command{Command_Type::Add, id, delay, interval, std::move(callback)});
         return id;
     }
     void push(Command command) {
@@ -82,36 +59,30 @@ struct Timer_Service::Impl {
         }
         cv.notify_one();
     }
-    void reset_wheel() {
-        wheel = std::make_unique<TimerWheel>();
-        last_update = std::chrono::steady_clock::now();
-    }
     void apply(Command&& command, bool& stop) {
         switch (command.type) {
         case Command_Type::Add: {
-            if (events.empty()) {
-                reset_wheel();
-            }
-            auto event = std::make_unique<Event>(this, command.id, command.interval, std::move(command.callback));
-            Event* ptr = event.get();
-            events.emplace(command.id, std::move(event));
-            wheel->schedule(ptr, command.delay);
+            scheduler.schedule(
+                command.id,
+                command.delay,
+                command.interval,
+                std::move(command.callback));
             break;
         }
         case Command_Type::Cancel: {
-            auto it = events.find(command.id);
-            if (it != events.end()) {
-                it->second->cancel();
-                events.erase(it);
+            scheduler.cancel(command.id);
+            if (command.callback) {
+                try {
+                    command.callback();
+                }
+                catch (...) {
+                    std::terminate();
+                }
             }
             break;
         }
         case Command_Type::Reschedule: {
-            auto it = events.find(command.id);
-            if (it != events.end()) {
-                it->second->cancel();
-                wheel->schedule(it->second.get(), command.delay);
-            }
+            scheduler.reschedule(command.id, command.delay);
             break;
         }
         case Command_Type::Stop: stop = true;
@@ -128,56 +99,22 @@ struct Timer_Service::Impl {
             apply(std::move(command), stop);
         }
     }
-    void finish_events() {
-        for (Timer_Id id : completed) {
-            events.erase(id);
-        }
-        completed.clear();
-        Tick current = wheel->now();
-        for (Timer_Id id : repeating) {
-            auto it = events.find(id);
-            if (it == events.end()) {
-                continue;
-            }
-            Event& event = *it->second;
-            Tick previous = event.scheduled_at();
-            Tick periods = current >= previous ? (current - previous) / event.interval + 1 : 1;
-            Tick next = previous + periods * event.interval;
-            wheel->schedule(&event, std::max<Tick>(1, next - current));
-        }
-        repeating.clear();
-    }
-    void advance_to_now() {
-        if (events.empty()) {
-            return;
-        }
-        auto now = std::chrono::steady_clock::now();
-        auto elapsed = now - last_update;
-        Tick ticks = static_cast<Tick>(std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed).count() / std::chrono::duration_cast<std::chrono::nanoseconds>(Tick_Duration).count());
-        if (ticks == 0) {
-            return;
-        }
-        wheel->advance(ticks);
-        last_update += Tick_Duration * ticks;
-        finish_events();
-    }
     void run() {
         bool stop = false;
         while (!stop) {
-            advance_to_now();
+            scheduler.advance_to_current_time();
             drain(stop);
             if (stop) {
                 break;
             }
-            if (events.empty()) {
+            if (scheduler.empty()) {
                 std::unique_lock lock(mutex);
                 cv.wait(lock, [this] {
                     return !commands.empty();
                 });
                 continue;
             }
-            Tick wait_ticks = std::min(wheel->ticks_to_next_event(), Max_Wait_Ticks);
-            auto deadline = last_update + Tick_Duration * wait_ticks;
+            const auto deadline = scheduler.next_deadline(Maximum_Wait);
             std::unique_lock lock(mutex);
             if (!commands.empty()) {
                 continue;
@@ -186,10 +123,6 @@ struct Timer_Service::Impl {
                 return !commands.empty();
             });
         }
-        for (auto& [id, event] : events) {
-            event->cancel();
-        }
-        events.clear();
     }
 };
 Timer_Service& Timer_Service::instance() {
@@ -203,14 +136,29 @@ Timer_Id Timer_Service::schedule_after(std::chrono::nanoseconds delay, Callback
 }
 Timer_Id Timer_Service::schedule_every(std::chrono::nanoseconds interval, Callback callback) {
     if (interval <= std::chrono::nanoseconds::zero()) {
-        interval = Impl::Tick_Duration;
+        interval = std::chrono::nanoseconds{1};
     }
     return impl->schedule(interval, interval, std::move(callback));
 }
+std::expected<Timer_Id, Schedule_Every_Fps_Result> Timer_Service::schedule_every_fps(
+    double frames_per_second,
+    Callback callback) {
+    const auto interval =
+        detail::timer_interval_from_frames_per_second(frames_per_second);
+    if (!interval.has_value()) {
+        return std::unexpected(interval.error());
+    }
+    return schedule_every(*interval, std::move(callback));
+}
 void Timer_Service::reschedule(Timer_Id id, std::chrono::nanoseconds delay) {
-    impl->push(Impl::Command{Impl::Command_Type::Reschedule, id, Impl::to_ticks(delay)});
+    impl->push(Impl::Command{Impl::Command_Type::Reschedule, id, delay});
 }
-void Timer_Service::cancel(Timer_Id id) {
-    impl->push(Impl::Command{Impl::Command_Type::Cancel, id});
+void Timer_Service::cancel(Timer_Id id, Callback completion) {
+    impl->push(Impl::Command{
+        Impl::Command_Type::Cancel,
+        id,
+        {},
+        {},
+        std::move(completion)});
 }
 }
diff --git a/kernel/kernel/include/time_thread/Timer_Service.hpp b/kernel/kernel/include/time_thread/Timer_Service.hpp
index 72460bb..f76232d 100644
--- a/kernel/kernel/include/time_thread/Timer_Service.hpp
+++ b/kernel/kernel/include/time_thread/Timer_Service.hpp
@@ -1,18 +1,31 @@
 #pragma once
 #include <chrono>
 #include <cstdint>
+#include <expected>
 #include <functional>
 #include <memory>
 #include "global.hpp"
 namespace aethera {
 using Timer_Id = std::uint64_t;
+enum struct Schedule_Every_Fps_Result : std::uint8_t {
+    invalid_frames_per_second,
+    interval_out_of_range
+};
 struct Timer_Service : Non_Copyable {
     using Callback = std::function<void()>;
     static Timer_Service& instance();
+    // 多少秒后执行一次
     Timer_Id schedule_after(std::chrono::nanoseconds delay, Callback callback);
+    template <typename Rep, typename Period> Timer_Id schedule_after(std::chrono::duration<Rep, Period> delay, Callback callback);
+    // 循环执行
     Timer_Id schedule_every(std::chrono::nanoseconds interval, Callback callback);
+    template <typename Rep, typename Period> Timer_Id schedule_every(std::chrono::duration<Rep, Period> interval, Callback callback);
+    std::expected<Timer_Id, Schedule_Every_Fps_Result> schedule_every_fps(double frames_per_second, Callback callback);
+    // 推后下一次执行
     void reschedule(Timer_Id id, std::chrono::nanoseconds delay);
-    void cancel(Timer_Id id);
+    template <typename Rep, typename Period> void reschedule(Timer_Id id, std::chrono::duration<Rep, Period> delay);
+    // 异步取消；completion 在该计时器不存在在途或后续回调时执行。
+    void cancel(Timer_Id id, Callback completion);
 private:
     struct Impl;
     Timer_Service();
@@ -20,3 +33,4 @@ private:
     std::unique_ptr<Impl> impl;
 };
 }
+#include "Timer_Service.ipp"
diff --git a/kernel/kernel/include/time_thread/Timer_Service.ipp b/kernel/kernel/include/time_thread/Timer_Service.ipp
new file mode 100644
index 0000000..16761e7
--- /dev/null
+++ b/kernel/kernel/include/time_thread/Timer_Service.ipp
@@ -0,0 +1,78 @@
+#pragma once
+
+#include <algorithm>
+#include <cmath>
+#include <limits>
+#include <utility>
+
+namespace aethera::detail {
+template<typename Rep, typename Period>
+std::chrono::nanoseconds timer_duration_to_nanoseconds(
+    std::chrono::duration<Rep, Period> duration) noexcept {
+    using Floating_Nanoseconds =
+        std::chrono::duration<long double, std::nano>;
+    constexpr auto Maximum =
+        static_cast<long double>(
+            std::numeric_limits<std::chrono::nanoseconds::rep>::max());
+
+    const auto nanoseconds =
+        std::chrono::duration_cast<Floating_Nanoseconds>(duration).count();
+    if (!(nanoseconds > 0.0L)) {
+        return std::chrono::nanoseconds::zero();
+    }
+    if (!std::isfinite(nanoseconds) || nanoseconds >= Maximum) {
+        return std::chrono::nanoseconds::max();
+    }
+    return std::chrono::nanoseconds{
+        static_cast<std::chrono::nanoseconds::rep>(
+            std::ceil(nanoseconds))};
+}
+
+inline std::expected<std::chrono::nanoseconds, Schedule_Every_Fps_Result>
+timer_interval_from_frames_per_second(double frames_per_second) noexcept {
+    if (!std::isfinite(frames_per_second) || frames_per_second <= 0.0) {
+        return std::unexpected(
+            Schedule_Every_Fps_Result::invalid_frames_per_second);
+    }
+    constexpr long double Nanoseconds_Per_Second = 1'000'000'000.0L;
+    const long double interval =
+        Nanoseconds_Per_Second / static_cast<long double>(frames_per_second);
+    constexpr auto Maximum_Interval =
+        static_cast<long double>(
+            std::numeric_limits<std::chrono::nanoseconds::rep>::max());
+    if (!std::isfinite(interval) || interval > Maximum_Interval) {
+        return std::unexpected(
+            Schedule_Every_Fps_Result::interval_out_of_range);
+    }
+    return std::chrono::nanoseconds{
+        static_cast<std::chrono::nanoseconds::rep>(
+            std::max(1.0L, std::ceil(interval)))};
+}
+}
+
+namespace aethera {
+template<typename Rep, typename Period>
+Timer_Id Timer_Service::schedule_after(
+    std::chrono::duration<Rep, Period> delay,
+    Callback callback) {
+    return schedule_after(
+        detail::timer_duration_to_nanoseconds(delay),
+        std::move(callback));
+}
+
+template<typename Rep, typename Period>
+Timer_Id Timer_Service::schedule_every(
+    std::chrono::duration<Rep, Period> interval,
+    Callback callback) {
+    return schedule_every(
+        detail::timer_duration_to_nanoseconds(interval),
+        std::move(callback));
+}
+
+template<typename Rep, typename Period>
+void Timer_Service::reschedule(
+    Timer_Id id,
+    std::chrono::duration<Rep, Period> delay) {
+    reschedule(id, detail::timer_duration_to_nanoseconds(delay));
+}
+}
diff --git a/kernel/kernel/include/time_thread/Timer_Time_Source.hpp b/kernel/kernel/include/time_thread/Timer_Time_Source.hpp
new file mode 100644
index 0000000..077f2a4
--- /dev/null
+++ b/kernel/kernel/include/time_thread/Timer_Time_Source.hpp
@@ -0,0 +1,12 @@
+#pragma once
+
+#include <chrono>
+
+namespace aethera {
+struct Timer_Time_Source {
+    using Time_Point = std::chrono::steady_clock::time_point;
+
+    virtual ~Timer_Time_Source() = default;
+    virtual Time_Point now() const noexcept = 0;
+};
+}
diff --git a/kernel/kernel/include/time_thread/detail/Timer_Scheduler.cpp b/kernel/kernel/include/time_thread/detail/Timer_Scheduler.cpp
new file mode 100644
index 0000000..7e1acd9
--- /dev/null
+++ b/kernel/kernel/include/time_thread/detail/Timer_Scheduler.cpp
@@ -0,0 +1,203 @@
+#include "Timer_Scheduler.hpp"
+
+#include "timer-wheel.h"
+
+#include <algorithm>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+namespace aethera::detail {
+struct Timer_Scheduler::Impl {
+    static constexpr std::chrono::microseconds Tick_Duration{10};
+
+    struct Event final : TimerEventInterface {
+        Impl& owner;
+        Timer_Id id;
+        Tick interval;
+        Timer_Service::Callback callback;
+
+        Event(Impl& owner,
+              Timer_Id id,
+              Tick interval,
+              Timer_Service::Callback callback) :
+            owner(owner),
+            id(id),
+            interval(interval),
+            callback(std::move(callback)) {}
+
+        void execute() override {
+            try {
+                callback();
+            }
+            catch (...) {}
+            if (interval == 0) {
+                owner.completed.emplace_back(id);
+                return;
+            }
+            owner.repeating.emplace_back(id);
+        }
+    };
+
+    explicit Impl(Timer_Time_Source& time_source) :
+        time_source(time_source) {}
+
+    static Tick to_ticks(std::chrono::nanoseconds duration) noexcept {
+        if (duration <= std::chrono::nanoseconds::zero()) {
+            return 1;
+        }
+        const auto nanoseconds = duration.count();
+        constexpr auto Tick_Nanoseconds =
+            std::chrono::duration_cast<std::chrono::nanoseconds>(
+                Tick_Duration).count();
+        return static_cast<Tick>(
+            nanoseconds / Tick_Nanoseconds +
+            (nanoseconds % Tick_Nanoseconds == 0 ? 0 : 1));
+    }
+
+    void reset_wheel() {
+        wheel = std::make_unique<TimerWheel>();
+        origin_time = time_source.now();
+    }
+
+    Timer_Time_Source::Time_Point current_tick_time() const noexcept {
+        return origin_time +
+            Tick_Duration * static_cast<std::int64_t>(wheel->now());
+    }
+
+    void schedule(Timer_Id id,
+                  std::chrono::nanoseconds delay,
+                  std::chrono::nanoseconds interval,
+                  Timer_Service::Callback callback) {
+        if (events.empty()) {
+            reset_wheel();
+        }
+        const Tick interval_ticks =
+            interval == std::chrono::nanoseconds::zero()
+                ? 0
+                : to_ticks(interval);
+        auto event = std::make_unique<Event>(
+            *this,
+            id,
+            interval_ticks,
+            std::move(callback));
+        wheel->schedule(event.get(), to_ticks(delay));
+        events.emplace(id, std::move(event));
+    }
+
+    void reschedule(Timer_Id id, std::chrono::nanoseconds delay) {
+        const auto event = events.find(id);
+        if (event == events.end()) {
+            return;
+        }
+        event->second->cancel();
+        wheel->schedule(event->second.get(), to_ticks(delay));
+    }
+
+    void cancel(Timer_Id id) {
+        const auto event = events.find(id);
+        if (event == events.end()) {
+            return;
+        }
+        event->second->cancel();
+        events.erase(event);
+    }
+
+    void finish_events() {
+        for (const Timer_Id id : completed) {
+            events.erase(id);
+        }
+        completed.clear();
+
+        const Tick current = wheel->now();
+        for (const Timer_Id id : repeating) {
+            const auto entry = events.find(id);
+            if (entry == events.end()) {
+                continue;
+            }
+            Event& event = *entry->second;
+            const Tick previous = event.scheduled_at();
+            const Tick periods = current >= previous
+                ? (current - previous) / event.interval + 1
+                : 1;
+            const Tick next = previous + periods * event.interval;
+            wheel->schedule(
+                std::addressof(event),
+                std::max<Tick>(1, next - current));
+        }
+        repeating.clear();
+    }
+
+    void advance_to_current_time() {
+        if (events.empty()) {
+            return;
+        }
+        const auto current_time = time_source.now();
+        const auto elapsed = current_time - current_tick_time();
+        if (elapsed < Tick_Duration) {
+            return;
+        }
+        const auto elapsed_nanoseconds =
+            std::chrono::duration_cast<std::chrono::nanoseconds>(elapsed);
+        constexpr auto Tick_Nanoseconds =
+            std::chrono::duration_cast<std::chrono::nanoseconds>(
+                Tick_Duration).count();
+        const Tick ticks = static_cast<Tick>(
+            elapsed_nanoseconds.count() / Tick_Nanoseconds);
+        wheel->advance(ticks);
+        finish_events();
+    }
+
+    Timer_Time_Source::Time_Point next_deadline(
+        std::chrono::nanoseconds maximum_wait) const {
+        const Tick wait_ticks = std::min(
+            wheel->ticks_to_next_event(),
+            to_ticks(maximum_wait));
+        return current_tick_time() +
+            Tick_Duration * static_cast<std::int64_t>(wait_ticks);
+    }
+
+    Timer_Time_Source& time_source; /* Required non-owning time authority. */
+    std::unique_ptr<TimerWheel> wheel{std::make_unique<TimerWheel>()};
+    std::unordered_map<Timer_Id, std::unique_ptr<Event>> events;
+    std::vector<Timer_Id> completed;
+    std::vector<Timer_Id> repeating;
+    Timer_Time_Source::Time_Point origin_time{};
+};
+
+Timer_Scheduler::Timer_Scheduler(Timer_Time_Source& time_source) :
+    impl(std::make_unique<Impl>(time_source)) {}
+
+Timer_Scheduler::~Timer_Scheduler() = default;
+
+void Timer_Scheduler::schedule(
+    Timer_Id id,
+    std::chrono::nanoseconds delay,
+    std::chrono::nanoseconds interval,
+    Timer_Service::Callback callback) {
+    impl->schedule(id, delay, interval, std::move(callback));
+}
+
+void Timer_Scheduler::reschedule(
+    Timer_Id id,
+    std::chrono::nanoseconds delay) {
+    impl->reschedule(id, delay);
+}
+
+void Timer_Scheduler::cancel(Timer_Id id) {
+    impl->cancel(id);
+}
+
+void Timer_Scheduler::advance_to_current_time() {
+    impl->advance_to_current_time();
+}
+
+bool Timer_Scheduler::empty() const noexcept {
+    return impl->events.empty();
+}
+
+Timer_Time_Source::Time_Point Timer_Scheduler::next_deadline(
+    std::chrono::nanoseconds maximum_wait) const {
+    return impl->next_deadline(maximum_wait);
+}
+}
diff --git a/kernel/kernel/include/time_thread/detail/Timer_Scheduler.hpp b/kernel/kernel/include/time_thread/detail/Timer_Scheduler.hpp
new file mode 100644
index 0000000..8894922
--- /dev/null
+++ b/kernel/kernel/include/time_thread/detail/Timer_Scheduler.hpp
@@ -0,0 +1,28 @@
+#pragma once
+
+#include "time_thread/Timer_Service.hpp"
+#include "time_thread/Timer_Time_Source.hpp"
+
+#include <chrono>
+#include <memory>
+
+namespace aethera::detail {
+struct Timer_Scheduler : Non_Copyable {
+    explicit Timer_Scheduler(Timer_Time_Source& time_source);
+    ~Timer_Scheduler();
+
+    void schedule(Timer_Id id,
+                  std::chrono::nanoseconds delay,
+                  std::chrono::nanoseconds interval,
+                  Timer_Service::Callback callback);
+    void reschedule(Timer_Id id, std::chrono::nanoseconds delay);
+    void cancel(Timer_Id id);
+    void advance_to_current_time();
+    [[nodiscard]] bool empty() const noexcept;
+    [[nodiscard]] Timer_Time_Source::Time_Point next_deadline(
+        std::chrono::nanoseconds maximum_wait) const;
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl;
+};
+}
diff --git a/kernel/kernel/test/function/frame_policy/Throttled_Latest_Only_Tests.cpp b/kernel/kernel/test/function/frame_policy/Throttled_Latest_Only_Tests.cpp
new file mode 100644
index 0000000..754832f
--- /dev/null
+++ b/kernel/kernel/test/function/frame_policy/Throttled_Latest_Only_Tests.cpp
@@ -0,0 +1,248 @@
+#include "function/frame_policy/detail/Throttled_Latest_Only_State.hpp"
+
+#include <gtest/gtest.h>
+
+#include <functional>
+#include <memory>
+#include <optional>
+#include <stdexcept>
+#include <utility>
+
+namespace {
+struct Frame_Policy_Test_Control {
+    void complete_render() {
+        ASSERT_TRUE(rendering_frame.has_value());
+        auto frame = *rendering_frame;
+        auto completion = std::move(render_completion);
+        rendering_frame.reset();
+        completion(frame.get());
+    }
+
+    void complete_send() {
+        ASSERT_TRUE(sending_frame.has_value());
+        auto frame = *sending_frame;
+        auto completion = std::move(send_completion);
+        sending_frame.reset();
+        completion(frame.get());
+    }
+
+    std::optional<std::reference_wrapper<aethera::proxy<aethera::FP_Frame>>>
+        rendering_frame;                        /* Scene 当前借用的策略帧。 */
+    std::optional<std::reference_wrapper<aethera::proxy<aethera::FP_Frame>>>
+        sending_frame;                          /* Sink 当前借用的策略帧。 */
+    aethera::FP_Frame_Completion render_completion; /* Scene 归还帧的完成回调。 */
+    aethera::FP_Frame_Completion send_completion;   /* Sink 归还帧的完成回调。 */
+    aethera::proxy<aethera::FP_Frame>* first_frame{}; /* 可空、非拥有的首次帧地址。 */
+    std::size_t frames_created{};               /* Scene 创建的物理帧数量。 */
+    std::size_t frames_alive{};                 /* 尚未析构的物理帧数量。 */
+    std::size_t render_calls{};                 /* 已接受的 Scene 借用次数。 */
+    std::size_t send_calls{};                   /* 已接受的 Sink 借用次数。 */
+    bool reused_same_frame{true};               /* 全部借用是否指向同一策略帧。 */
+    bool complete_render_synchronously{};       /* Scene 是否在 render 调用内立即归还帧。 */
+    bool complete_send_synchronously{};         /* Sink 是否在 send 调用内立即归还帧。 */
+    bool throw_from_send{};                     /* Sink 是否以 Unknown Failure 退出本次分派。 */
+};
+
+struct Test_Frame {
+    explicit Test_Frame(
+        std::shared_ptr<Frame_Policy_Test_Control> control) :
+        control(std::move(control)) {
+        ++this->control->frames_alive;
+    }
+
+    Test_Frame(Test_Frame&& other) noexcept :
+        control(std::move(other.control)) {}
+    Test_Frame& operator=(Test_Frame&&) = delete;
+    Test_Frame(const Test_Frame&) = delete;
+    Test_Frame& operator=(const Test_Frame&) = delete;
+
+    ~Test_Frame() {
+        if (control) {
+            --control->frames_alive;
+        }
+    }
+
+    aethera::Time_Type use_time() {
+        return 0;
+    }
+
+    std::shared_ptr<Frame_Policy_Test_Control> control; /* 测试帧生命周期记录的共享所有权。 */
+};
+
+struct Test_Scene {
+    aethera::proxy<aethera::FP_Frame> create_frame() {
+        ++control->frames_created;
+        return pro::make_proxy<aethera::FP_Frame, Test_Frame>(control);
+    }
+
+    void render(
+        aethera::proxy<aethera::FP_Frame>& frame,
+        aethera::FP_Frame_Completion completion) {
+        if (control->first_frame == nullptr) {
+            control->first_frame = std::addressof(frame);
+        }
+        control->reused_same_frame =
+            control->reused_same_frame &&
+            control->first_frame == std::addressof(frame);
+        ++control->render_calls;
+        if (control->complete_render_synchronously) {
+            completion(frame);
+            return;
+        }
+        control->rendering_frame = frame;
+        control->render_completion = std::move(completion);
+    }
+
+    std::shared_ptr<Frame_Policy_Test_Control> control; /* Scene 测试行为的共享控制数据。 */
+};
+
+struct Test_Sink {
+    void send(
+        aethera::proxy<aethera::FP_Frame>& frame,
+        aethera::FP_Frame_Completion completion) {
+        control->reused_same_frame =
+            control->reused_same_frame &&
+            control->first_frame == std::addressof(frame);
+        ++control->send_calls;
+        if (control->throw_from_send) {
+            throw std::runtime_error("test sink failure");
+        }
+        if (control->complete_send_synchronously) {
+            completion(frame);
+            return;
+        }
+        control->sending_frame = frame;
+        control->send_completion = std::move(completion);
+    }
+
+    std::shared_ptr<Frame_Policy_Test_Control> control; /* Sink 测试行为的共享控制数据。 */
+};
+
+std::shared_ptr<aethera::detail::Throttled_Latest_Only_State>
+make_state(const std::shared_ptr<Frame_Policy_Test_Control>& control) {
+    auto scene =
+        pro::make_proxy<aethera::FP_Scene, Test_Scene>(control);
+    auto sink =
+        pro::make_proxy<aethera::FP_Sink, Test_Sink>(control);
+    return std::make_shared<
+        aethera::detail::Throttled_Latest_Only_State>(
+            std::move(scene),
+            std::move(sink));
+}
+
+TEST(Throttled_Latest_Only, Reuses_One_Scene_Created_Frame_And_Drops_Busy_Ticks) {
+    auto control = std::make_shared<Frame_Policy_Test_Control>();
+    auto state = make_state(control);
+    ASSERT_EQ(
+        state->prepare_start(),
+        aethera::Start_Throttled_Latest_Only_Result::started);
+    state->timer_started(7);
+    EXPECT_EQ(control->frames_created, 1);
+    EXPECT_EQ(control->frames_alive, 1);
+
+    state->frame_due();
+    state->frame_due();
+    EXPECT_EQ(control->render_calls, 1);
+    EXPECT_EQ(control->send_calls, 0);
+
+    control->complete_render();
+    state->frame_due();
+    EXPECT_EQ(control->render_calls, 1);
+    EXPECT_EQ(control->send_calls, 1);
+    control->complete_send();
+
+    state->frame_due();
+    EXPECT_EQ(control->render_calls, 2);
+    control->complete_render();
+    control->complete_send();
+    EXPECT_TRUE(control->reused_same_frame);
+
+    bool stopped = false;
+    const auto stop = state->request_stop([&stopped] {
+        stopped = true;
+    });
+    ASSERT_EQ(
+        stop.result,
+        aethera::Stop_Throttled_Latest_Only_Result::stopping);
+    ASSERT_EQ(stop.timer_id, 7);
+    state->timer_cancelled();
+
+    EXPECT_TRUE(stopped);
+    EXPECT_EQ(control->frames_alive, 0);
+    EXPECT_TRUE(state->destructible());
+}
+
+TEST(Throttled_Latest_Only, Stop_Waits_For_Render_And_Send_Borrows_To_Return) {
+    auto control = std::make_shared<Frame_Policy_Test_Control>();
+    auto state = make_state(control);
+    ASSERT_EQ(
+        state->prepare_start(),
+        aethera::Start_Throttled_Latest_Only_Result::started);
+    state->timer_started(11);
+    state->frame_due();
+
+    bool stopped = false;
+    const auto stop = state->request_stop([&stopped] {
+        stopped = true;
+    });
+    ASSERT_EQ(
+        stop.result,
+        aethera::Stop_Throttled_Latest_Only_Result::stopping);
+    state->timer_cancelled();
+    EXPECT_FALSE(stopped);
+    EXPECT_EQ(control->frames_alive, 1);
+
+    control->complete_render();
+    EXPECT_FALSE(stopped);
+    EXPECT_EQ(control->send_calls, 1);
+    EXPECT_EQ(control->frames_alive, 1);
+
+    control->complete_send();
+    EXPECT_TRUE(stopped);
+    EXPECT_EQ(control->frames_alive, 0);
+    EXPECT_TRUE(state->destructible());
+}
+
+TEST(Throttled_Latest_Only, Reports_Missing_Dependencies_And_Stop_Completion) {
+    auto missing_dependencies = std::make_shared<
+        aethera::detail::Throttled_Latest_Only_State>(
+            aethera::proxy<aethera::FP_Scene>{},
+            aethera::proxy<aethera::FP_Sink>{});
+
+    EXPECT_EQ(
+        missing_dependencies->prepare_start(),
+        aethera::Start_Throttled_Latest_Only_Result::dependency_unavailable);
+    EXPECT_EQ(
+        missing_dependencies->request_stop({}).result,
+        aethera::Stop_Throttled_Latest_Only_Result::completion_missing);
+    EXPECT_TRUE(missing_dependencies->destructible());
+}
+
+TEST(Throttled_Latest_Only, Synchronous_Completions_And_Failure_Restore_The_Frame) {
+    auto control = std::make_shared<Frame_Policy_Test_Control>();
+    control->complete_render_synchronously = true;
+    control->throw_from_send = true;
+    auto state = make_state(control);
+    ASSERT_EQ(
+        state->prepare_start(),
+        aethera::Start_Throttled_Latest_Only_Result::started);
+    state->timer_started(13);
+
+    EXPECT_THROW(state->frame_due(), std::runtime_error);
+    control->throw_from_send = false;
+    control->complete_send_synchronously = true;
+    EXPECT_NO_THROW(state->frame_due());
+    EXPECT_EQ(control->render_calls, 2);
+    EXPECT_EQ(control->send_calls, 2);
+
+    bool stopped = false;
+    ASSERT_EQ(
+        state->request_stop([&stopped] {
+            stopped = true;
+        }).result,
+        aethera::Stop_Throttled_Latest_Only_Result::stopping);
+    state->timer_cancelled();
+    EXPECT_TRUE(stopped);
+    EXPECT_TRUE(state->destructible());
+}
+}
diff --git a/kernel/kernel/test/task_flow/Taskflow_Observation_Tests.cpp b/kernel/kernel/test/task_flow/Taskflow_Observation_Tests.cpp
new file mode 100644
index 0000000..2b03e60
--- /dev/null
+++ b/kernel/kernel/test/task_flow/Taskflow_Observation_Tests.cpp
@@ -0,0 +1,153 @@
+#include "task_flow/Task_Runtime.hpp"
+#include "task_flow/detail/Taskflow_Execution.ipp"
+
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <concepts>
+#include <memory>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+
+namespace {
+
+using Run_Without_Observation = aethera::Run_Taskflow_Result(*)(
+    aethera::Task_Graph&,
+    aethera::Taskflow_Completion);
+using Run_With_Observation = aethera::Run_Taskflow_Result(*)(
+    aethera::Task_Graph&,
+    aethera::Taskflow_Completion,
+    aethera::Taskflow_Observation);
+
+static_assert(!std::default_initializable<aethera::Taskflow_Observation>);
+static_assert(std::constructible_from<
+              aethera::Taskflow_Observation,
+              std::string>);
+static_assert(std::same_as<
+              decltype(static_cast<Run_Without_Observation>(
+                  &aethera::run_taskflow)),
+              Run_Without_Observation>);
+static_assert(std::same_as<
+              decltype(static_cast<Run_With_Observation>(
+                  &aethera::run_taskflow)),
+              Run_With_Observation>);
+
+struct Taskflow_Observation_Test : testing::Test {
+    Taskflow_Observation_Test() {
+        aethera::Taskflow_Node_Trace node{};
+        node.native_id = native_id;
+        node.node_id = "test.graph/task";
+        node.name = "task";
+        node.type = "static";
+        nodes.push_back(std::move(node));
+    }
+
+    static constexpr std::uint64_t native_id{17};
+    aethera::Taskflow_Observation observation{"test.stage"}; /* 本测试共享的显式记录请求。 */
+    std::vector<aethera::Taskflow_Node_Trace> nodes{};        /* 本次执行使用的静态节点定义。 */
+};
+
+TEST_F(Taskflow_Observation_Test, Explicit_Request_Records_And_Consumes_One_Trace) {
+    auto execution =
+        aethera::detail::Taskflow_Observation_Execution::try_start(
+            observation,
+            1,
+            "test.graph",
+            nodes);
+    ASSERT_TRUE(execution.has_value());
+    EXPECT_EQ(
+        execution->binding(),
+        static_cast<void*>(std::addressof(*execution)));
+
+    const auto entered = std::chrono::steady_clock::now();
+    execution->observe_entry(0, native_id, 3, 8, entered);
+    execution->observe_exit(
+        0,
+        native_id,
+        std::chrono::steady_clock::now());
+    execution->finish(std::chrono::steady_clock::now());
+
+    auto trace = observation.take();
+    ASSERT_TRUE(trace.has_value());
+    EXPECT_EQ(trace->stage, "test.stage");
+    EXPECT_EQ(trace->taskflow_name, "test.graph");
+    ASSERT_EQ(trace->nodes.size(), 1);
+    EXPECT_EQ(trace->nodes.front().native_id, native_id);
+    ASSERT_EQ(trace->worker_tasks.size(), 1);
+    ASSERT_EQ(trace->worker_tasks.front().size(), 1);
+    const auto& task = trace->worker_tasks.front().front();
+    EXPECT_EQ(task.native_id, native_id);
+    EXPECT_EQ(task.worker_queue_size, 3);
+    EXPECT_EQ(task.worker_queue_capacity, 8);
+    EXPECT_GE(task.completed_ms, task.finished_ms);
+}
+
+TEST_F(Taskflow_Observation_Test, Cancelled_Start_Preserves_The_Only_Stage_Value) {
+    {
+        auto cancelled =
+            aethera::detail::Taskflow_Observation_Execution::try_start(
+                observation,
+                1,
+                "cancelled.graph",
+                nodes);
+        ASSERT_TRUE(cancelled.has_value());
+    }
+
+    auto restarted =
+        aethera::detail::Taskflow_Observation_Execution::try_start(
+            observation,
+            1,
+            "completed.graph",
+            nodes);
+    ASSERT_TRUE(restarted.has_value());
+    restarted->finish(std::chrono::steady_clock::now());
+
+    auto trace = observation.take();
+    ASSERT_TRUE(trace.has_value());
+    EXPECT_EQ(trace->stage, "test.stage");
+    EXPECT_EQ(trace->taskflow_name, "completed.graph");
+}
+
+TEST_F(Taskflow_Observation_Test, Copied_Handles_Consume_One_Authoritative_Result) {
+    auto copy = observation;
+    auto execution =
+        aethera::detail::Taskflow_Observation_Execution::try_start(
+            observation,
+            1,
+            "test.graph",
+            nodes);
+    ASSERT_TRUE(execution.has_value());
+    execution->finish(std::chrono::steady_clock::now());
+
+    ASSERT_TRUE(copy.take().has_value());
+    const auto second = observation.take();
+    ASSERT_FALSE(second.has_value());
+    EXPECT_EQ(
+        second.error(),
+        aethera::Take_Taskflow_Observation_Result::already_taken);
+}
+
+TEST(Taskflow_Observation_Execution, Missing_Request_Has_No_Observer_Binding) {
+    aethera::detail::Taskflow_Observation_Execution execution;
+    EXPECT_EQ(execution.binding(), nullptr);
+}
+
+TEST_F(Taskflow_Observation_Test, Moved_From_Request_Is_Unavailable_Not_Disabled) {
+    auto owner = std::move(observation);
+    const auto execution =
+        aethera::detail::Taskflow_Observation_Execution::try_start(
+            observation,
+            1,
+            "test.graph",
+            nodes);
+    ASSERT_FALSE(execution.has_value());
+    EXPECT_EQ(
+        execution.error(),
+        aethera::detail::Start_Taskflow_Observation_Result::unavailable);
+    EXPECT_EQ(owner.take().error(),
+              aethera::Take_Taskflow_Observation_Result::not_recorded);
+}
+
+}
diff --git a/kernel/kernel/test/time_thread/Timer_Service_Tests.cpp b/kernel/kernel/test/time_thread/Timer_Service_Tests.cpp
new file mode 100644
index 0000000..6076b56
--- /dev/null
+++ b/kernel/kernel/test/time_thread/Timer_Service_Tests.cpp
@@ -0,0 +1,182 @@
+#include "time_thread/Timer_Service.hpp"
+#include "time_thread/Timer_Time_Source.hpp"
+#include "time_thread/detail/Timer_Scheduler.hpp"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <chrono>
+#include <concepts>
+#include <limits>
+
+namespace {
+
+using namespace std::chrono_literals;
+
+template<typename Duration>
+concept Timer_Duration_Api = requires(
+    aethera::Timer_Service& service,
+    aethera::Timer_Id id,
+    Duration duration,
+    aethera::Timer_Service::Callback callback) {
+    { service.schedule_after(duration, callback) } ->
+        std::same_as<aethera::Timer_Id>;
+    { service.schedule_every(duration, callback) } ->
+        std::same_as<aethera::Timer_Id>;
+    { service.reschedule(id, duration) } -> std::same_as<void>;
+};
+
+static_assert(Timer_Duration_Api<std::chrono::milliseconds>);
+static_assert(Timer_Duration_Api<std::chrono::duration<double>>);
+static_assert(Timer_Duration_Api<
+              std::chrono::duration<double, std::ratio<1, 3>>>);
+
+struct Mock_Timer_Time_Source : aethera::Timer_Time_Source {
+    MOCK_METHOD(Time_Point, now, (), (const, noexcept, override));
+};
+
+struct Timer_Scheduler_Test : testing::Test {
+    Timer_Scheduler_Test() {
+        EXPECT_CALL(time_source, now())
+            .Times(testing::AnyNumber())
+            .WillRepeatedly([this] {
+                return current_time;
+            });
+    }
+
+    void advance_by(std::chrono::nanoseconds duration) {
+        current_time += duration;
+        scheduler.advance_to_current_time();
+    }
+
+    aethera::Timer_Time_Source::Time_Point current_time{};
+    testing::StrictMock<Mock_Timer_Time_Source> time_source;
+    aethera::detail::Timer_Scheduler scheduler{time_source};
+};
+
+TEST(Timer_Service_Duration, Converts_Integral_Floating_And_Subnanosecond_Units) {
+    EXPECT_EQ(
+        aethera::detail::timer_duration_to_nanoseconds(2ms),
+        2'000'000ns);
+    EXPECT_EQ(
+        aethera::detail::timer_duration_to_nanoseconds(
+            std::chrono::duration<double, std::milli>{1.5}),
+        1'500'000ns);
+    EXPECT_EQ(
+        aethera::detail::timer_duration_to_nanoseconds(
+            std::chrono::duration<double, std::nano>{0.25}),
+        1ns);
+    EXPECT_EQ(
+        aethera::detail::timer_duration_to_nanoseconds(-1s),
+        0ns);
+    EXPECT_EQ(
+        aethera::detail::timer_duration_to_nanoseconds(
+            std::chrono::duration<long double>{
+                std::numeric_limits<long double>::infinity()}),
+        std::chrono::nanoseconds::max());
+}
+
+TEST(Timer_Service_Fps, Converts_Fractional_Frame_Rates_And_Rejects_Invalid_Values) {
+    const auto fifty_fps =
+        aethera::detail::timer_interval_from_frames_per_second(50.0);
+    const auto fractional_fps =
+        aethera::detail::timer_interval_from_frames_per_second(29.97);
+    ASSERT_TRUE(fifty_fps.has_value());
+    EXPECT_EQ(*fifty_fps, 20ms);
+    ASSERT_TRUE(fractional_fps.has_value());
+    EXPECT_NEAR(
+        static_cast<double>(fractional_fps->count()),
+        33'366'700.0,
+        1.0);
+
+    const auto zero =
+        aethera::detail::timer_interval_from_frames_per_second(0.0);
+    const auto negative =
+        aethera::detail::timer_interval_from_frames_per_second(-60.0);
+    const auto infinite =
+        aethera::detail::timer_interval_from_frames_per_second(
+            std::numeric_limits<double>::infinity());
+    const auto not_a_number =
+        aethera::detail::timer_interval_from_frames_per_second(
+            std::numeric_limits<double>::quiet_NaN());
+    const auto too_slow =
+        aethera::detail::timer_interval_from_frames_per_second(
+            std::numeric_limits<double>::denorm_min());
+
+    ASSERT_FALSE(zero.has_value());
+    EXPECT_EQ(
+        zero.error(),
+        aethera::Schedule_Every_Fps_Result::invalid_frames_per_second);
+    ASSERT_FALSE(negative.has_value());
+    EXPECT_EQ(
+        negative.error(),
+        aethera::Schedule_Every_Fps_Result::invalid_frames_per_second);
+    ASSERT_FALSE(infinite.has_value());
+    EXPECT_EQ(
+        infinite.error(),
+        aethera::Schedule_Every_Fps_Result::invalid_frames_per_second);
+    ASSERT_FALSE(not_a_number.has_value());
+    EXPECT_EQ(
+        not_a_number.error(),
+        aethera::Schedule_Every_Fps_Result::invalid_frames_per_second);
+    ASSERT_FALSE(too_slow.has_value());
+    EXPECT_EQ(
+        too_slow.error(),
+        aethera::Schedule_Every_Fps_Result::interval_out_of_range);
+}
+
+TEST_F(Timer_Scheduler_Test, After_Fires_Only_When_Mock_Time_Reaches_Deadline) {
+    testing::StrictMock<testing::MockFunction<void()>> callback;
+    EXPECT_CALL(callback, Call()).Times(0);
+    scheduler.schedule(1, 25us, 0ns, callback.AsStdFunction());
+
+    advance_by(29us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(1);
+    advance_by(1us);
+    EXPECT_TRUE(scheduler.empty());
+}
+
+TEST_F(Timer_Scheduler_Test, Every_Uses_Mock_Time_Without_Drifting_Early) {
+    testing::StrictMock<testing::MockFunction<void()>> callback;
+    scheduler.schedule(2, 20us, 20us, callback.AsStdFunction());
+
+    EXPECT_CALL(callback, Call()).Times(0);
+    advance_by(19us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(1);
+    advance_by(1us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(0);
+    advance_by(19us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(1);
+    advance_by(1us);
+    scheduler.cancel(2);
+}
+
+TEST_F(Timer_Scheduler_Test, Reschedule_And_Cancel_Use_The_Same_Time_Authority) {
+    testing::StrictMock<testing::MockFunction<void()>> callback;
+    scheduler.schedule(3, 100us, 0ns, callback.AsStdFunction());
+    scheduler.reschedule(3, 25us);
+
+    EXPECT_CALL(callback, Call()).Times(0);
+    advance_by(29us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(1);
+    advance_by(1us);
+    testing::Mock::VerifyAndClearExpectations(&callback);
+
+    EXPECT_CALL(callback, Call()).Times(0);
+    scheduler.schedule(4, 20us, 0ns, callback.AsStdFunction());
+    scheduler.cancel(4);
+    advance_by(200us);
+    EXPECT_TRUE(scheduler.empty());
+}
+
+}
diff --git a/kernel/main.cmake b/kernel/main.cmake
index f655bd7..7fd523a 100644
--- a/kernel/main.cmake
+++ b/kernel/main.cmake
@@ -58,7 +58,10 @@ if (Aethera_BUILD_TESTS)
 
     append_glob_source(Aethera_Kernel_module_test_sources
             "${Aethera_Kernel_test_dir}/concurrent"
-            "${Aethera_Kernel_test_dir}/model")
+            "${Aethera_Kernel_test_dir}/model"
+            "${Aethera_Kernel_test_dir}/task_flow"
+            "${Aethera_Kernel_test_dir}/time_thread"
+            "${Aethera_Kernel_test_dir}/function/frame_policy")
     foreach (Aethera_Kernel_module_test_source IN LISTS Aethera_Kernel_module_test_sources)
         if (NOT Aethera_Kernel_module_test_source MATCHES "\\.(c|cc|cpp|cxx)$")
             continue()
@@ -71,7 +74,8 @@ if (Aethera_BUILD_TESTS)
                 "${Aethera_Kernel_module_test_source}")
         target_link_libraries("${Aethera_Kernel_module_test_target}" PRIVATE
                 Aethera_Kernel
-                GTest::gtest_main)
+                GTest::gtest_main
+                GTest::gmock)
         add_test(NAME "${Aethera_Kernel_module_test_target}"
                 COMMAND "${Aethera_Kernel_cdb}" -c "g;q"
                 "$<TARGET_FILE:${Aethera_Kernel_module_test_target}>")