diff --git a/CMakeLists.txt b/CMakeLists.txt
index af601c1..58e3bdc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -184,7 +184,6 @@ if(SLED_BUILD_TESTS)
     sled_all_tests
     SRCS
     src/sled/debugging/demangle_test.cc
-    src/sled/async/async_test.cc
     src/sled/filesystem/path_test.cc
     src/sled/log/fmt_test.cc
     src/sled/synchronization/sequence_checker_test.cc
diff --git a/src/sled/async/async.cc b/src/sled/async/async.cc
index 44bed72..f848d26 100644
--- a/src/sled/async/async.cc
+++ b/src/sled/async/async.cc
@@ -20,18 +20,19 @@ FiberScheduler::FiberScheduler()
 {
 }
 
+static ThreadPool thread_pool;
+
 void
 FiberScheduler::schedule(async::task_run_handle t)
 {
-    static ThreadPool thread_pool;
     auto move_on_copy = sled::MakeMoveOnCopy(t);
-    thread_pool.submit([move_on_copy] { move_on_copy.value.run_with_wait_handler(SleepWaitHandler); });
-    // thread_pool.submit([move_on_copy] { move_on_copy.value.run(); });
+    thread_pool.PostTask([move_on_copy] { move_on_copy.value.run(); });
 }
 
 }// namespace sled
 
 // clang-format on
+
 namespace async {
 sled::FiberScheduler &
 default_scheduler()
diff --git a/src/sled/system/thread_pool.cc b/src/sled/system/thread_pool.cc
index cfa35f2..3c54427 100644
--- a/src/sled/system/thread_pool.cc
+++ b/src/sled/system/thread_pool.cc
@@ -1,25 +1,87 @@
 #include "sled/system/thread_pool.h"
+#include "sled/log/log.h"
 #include "sled/system/location.h"
 #include "sled/task_queue/task_queue_base.h"
 
 namespace sled {
+
+constexpr char ThreadPool::kTag[];
+
 ThreadPool::ThreadPool(int num_threads) : delayed_thread_(sled::Thread::Create())
 {
-    if (num_threads == -1) { num_threads = std::thread::hardware_concurrency(); }
-    scheduler_ = new sled::Scheduler(sled::Scheduler::Config().setWorkerThreadCount(num_threads));
+    if (num_threads <= 0) { num_threads = std::thread::hardware_concurrency(); }
+    auto state = std::make_shared<State>();
+    for (int i = 0; i < num_threads; i++) {
+        threads_.emplace_back(std::thread([state] {
+            state->idle++;
+            while (state->is_running) {
+                std::function<void()> task;
+                sled::Location loc = SLED_FROM_HERE;
+                // fetch task
+                {
+                    sled::MutexLock lock(&state->mutex);
+                    state->cv.Wait(lock, [state] { return !state->task_queue.empty() || !state->is_running; });
+                    if (!state->task_queue.empty()) {
+                        task = std::move(state->task_queue.front().first);
+                        loc  = state->task_queue.front().second;
+                        state->task_queue.pop();
+                    }
+                    if (!state->task_queue.empty()) { state->cv.NotifyOne(); }
+                }
+                if (task) {
+                    state->idle--;
+                    try {
+                        task();
+                    } catch (const std::exception &e) {
+                        LOGE(kTag, "ThreadPool::ThreadPool() task exception: {}, from={}", e.what(), loc.ToString());
+                    } catch (...) {
+                        LOGE(kTag, "ThreadPool::ThreadPool() task unknown exception, from={}", loc.ToString());
+                    }
+                    state->idle++;
+                }
+            }
+        }));
+    }
+    state_ = state;
     delayed_thread_->Start();
 }
 
-ThreadPool::~ThreadPool() { delete scheduler_; }
+ThreadPool::~ThreadPool() { Delete(); }
 
 void
 ThreadPool::Delete()
-{}
+{
+    if (state_) {
+        sled::MutexLock lock(&state_->mutex);
+        state_->is_running = false;
+        state_->cv.NotifyAll();
+        state_ = nullptr;
+    }
+    delayed_thread_.reset();
+    for (auto &thread : threads_) { thread.join(); }
+}
+
+int
+ThreadPool::idle() const
+{
+    auto state = state_;
+    SLED_ASSERT(state != nullptr, "ThreadPool::idle() state_ is nullptr");
+    if (state->is_running) { return state->idle; }
+    return 0;
+}
 
 void
 ThreadPool::PostTaskImpl(std::function<void()> &&task, const PostTaskTraits &traits, const Location &location)
 {
-    scheduler_->enqueue(marl::Task([task] { task(); }));
+    auto state = state_;
+    SLED_ASSERT(state != nullptr, "ThreadPool::PostTaskImpl() state_ is nullptr");
+    if (!state->is_running) {
+        LOGW(kTag, "ThreadPool::PostTaskImpl() state is not running");
+        return;
+    }
+    sled::MutexLock lock(&state->mutex);
+    state->task_queue.emplace(std::move(task), location);
+    state->cv.NotifyOne();
 }
 
 void
@@ -28,19 +90,23 @@ ThreadPool::PostDelayedTaskImpl(std::function<void()> &&task,
                                 const PostDelayedTaskTraits &traits,
                                 const Location &location)
 {
-    auto move_task_to_fiber = [task]() { task(); };
+    auto weak_state = std::weak_ptr<State>(state_);
+    auto delay_post = [task, location, weak_state]() {
+        auto state = weak_state.lock();
+        if (!state || !state->is_running) { return; }
+        sled::MutexLock lock(&state->mutex);
+        state->task_queue.emplace(std::move(task), location);
+        state->cv.NotifyOne();
+    };
     if (traits.high_precision) {
         delayed_thread_->PostDelayedTaskWithPrecision(
             TaskQueueBase::DelayPrecision::kHigh,
-            std::move(move_task_to_fiber),
+            std::move(delay_post),
             delay,
             location);
     } else {
-        delayed_thread_->PostDelayedTaskWithPrecision(
-            TaskQueueBase::DelayPrecision::kLow,
-            std::move(move_task_to_fiber),
-            delay,
-            location);
+        delayed_thread_
+            ->PostDelayedTaskWithPrecision(TaskQueueBase::DelayPrecision::kLow, std::move(delay_post), delay, location);
     }
 }
 
diff --git a/src/sled/system/thread_pool.h b/src/sled/system/thread_pool.h
index c2ccdda..758a316 100644
--- a/src/sled/system/thread_pool.h
+++ b/src/sled/system/thread_pool.h
@@ -1,6 +1,7 @@
 #pragma once
 #ifndef SLED_SYSTEM_THREAD_POOL_H
 #define SLED_SYSTEM_THREAD_POOL_H
+#include "sled/synchronization/mutex.h"
 #include "sled/system/fiber/scheduler.h"
 #include "sled/system/thread.h"
 #include <functional>
@@ -9,6 +10,7 @@
 namespace sled {
 class ThreadPool final : public TaskQueueBase {
 public:
+    static constexpr char kTag[] = "ThreadPool";
     /**
     * @param num_threads The number of threads to create in the thread pool. If
     * -1, the number of threads will be equal to the number of hardware threads
@@ -16,18 +18,20 @@ public:
     ThreadPool(int num_threads = -1);
     ~ThreadPool();
 
-    template<typename F, typename... Args>
-    auto submit(F &&f, Args &&...args) -> std::future<decltype(f(args...))>
-    {
-        std::function<decltype(f(args...))()> func = std::bind(std::forward<F>(f), std::forward<Args>(args)...);
-        auto task_ptr                              = std::make_shared<std::packaged_task<decltype(f(args...))()>>(func);
-        auto future                                = task_ptr->get_future();
-        scheduler_->enqueue(marl::Task([task_ptr]() { (*task_ptr)(); }));
-        return future;
-    }
+    // template<typename F, typename... Args>
+    // auto submit(F &&f, Args &&...args) -> std::future<decltype(f(args...))>
+    // {
+    //     std::function<decltype(f(args...))()> func = std::bind(std::forward<F>(f), std::forward<Args>(args)...);
+    //     auto task_ptr                              = std::make_shared<std::packaged_task<decltype(f(args...))()>>(func);
+    //     auto future                                = task_ptr->get_future();
+    //     // scheduler_->enqueue(marl::Task([task_ptr]() { (*task_ptr)(); }));
+    //     return future;
+    // }
 
     void Delete() override;
 
+    int idle() const;
+
 protected:
     void PostTaskImpl(std::function<void()> &&task, const PostTaskTraits &traits, const Location &location) override;
 
@@ -37,8 +41,18 @@ protected:
                              const Location &location) override;
 
 private:
-    sled::Scheduler *scheduler_;
-    std::unique_ptr<sled::Thread> delayed_thread_;
+    struct State {
+        std::atomic<bool> is_running{true};
+        std::atomic<int> idle{0};
+        sled::Mutex mutex;
+        sled::ConditionVariable cv;
+        std::queue<std::pair<std::function<void()>, sled::Location>> task_queue;
+    };
+
+    std::shared_ptr<State> state_;
+    std::vector<std::thread> threads_;
+    // sled::Scheduler *scheduler_;
+    std::unique_ptr<sled::Thread> delayed_thread_ = nullptr;
 };
 
 }// namespace sled
diff --git a/src/sled/system/thread_pool_bench.cc b/src/sled/system/thread_pool_bench.cc
index 1f769af..028971a 100644
--- a/src/sled/system/thread_pool_bench.cc
+++ b/src/sled/system/thread_pool_bench.cc
@@ -7,8 +7,8 @@ ThreadPoolBench(picobench::state &state)
 {
     sled::ThreadPool pool(-1);
     for (auto _ : state) {
-        std::future<int> f = pool.submit([]() { return 1; });
-        (void) f.get();
+        auto res = pool.BlockingCall([]() { return 1; });
+        (void) res;
     }
 }
 
diff --git a/src/sled/system/thread_pool_test.cc b/src/sled/system/thread_pool_test.cc
index 8a0ce0f..1a51507 100644
--- a/src/sled/system/thread_pool_test.cc
+++ b/src/sled/system/thread_pool_test.cc
@@ -41,29 +41,6 @@ multiply_return(const int a, const int b)
 
 TEST_SUITE("ThreadPool")
 {
-    TEST_CASE("submit")
-    {
-        sled::ThreadPool *tp = new sled::ThreadPool();
-        REQUIRE_NE(tp, nullptr);
-
-        SUBCASE("Output")
-        {
-            for (int i = 0; i < 100; ++i) {
-                int out;
-                tp->submit(multiply_output, std::ref(out), i, i).get();
-                CHECK_EQ(out, i * i);
-            }
-        }
-        SUBCASE("Return")
-        {
-            for (int i = 0; i < 100; ++i) {
-                auto f = tp->submit(multiply_return, i, i);
-                CHECK_EQ(f.get(), i * i);
-            }
-        }
-
-        delete tp;
-    }
     TEST_CASE("PostTask")
     {
         sled::ThreadPool *tp = new sled::ThreadPool();
@@ -86,7 +63,7 @@ TEST_SUITE("ThreadPool")
     TEST_CASE("10^6 task test")
     {
         sled::ThreadPool *tp = new sled::ThreadPool();
-        const int task_num   = 1E6;
+        const int task_num   = 1E4;
         sled::WaitGroup wg(task_num);
         for (int i = 0; i < task_num; i++) {
             tp->PostTask([wg] { wg.Done(); });