diff --git a/build/src.pro b/build/src.pro
index e279c7a..a446988 100644
--- a/build/src.pro
+++ b/build/src.pro
@@ -26,7 +26,10 @@ HEADERS += \
     ../include/tls_pointer.h \
     ../src/channel.inc \
     ../src/route.inc \
-    ../src/id_pool.inc
+    ../src/id_pool.inc \
+    ../src/memory/alloc.hpp \
+    ../src/memory/wrapper.hpp \
+    ../src/memory/resource.hpp
 
 SOURCES += \
     ../src/shm.cpp \
diff --git a/include/circ_queue.h b/include/circ_queue.h
index ccbd1f0..81e32bc 100644
--- a/include/circ_queue.h
+++ b/include/circ_queue.h
@@ -7,7 +7,6 @@
 #include <atomic>
 #include <tuple>
 #include <thread>
-#include <chrono>
 
 #include "def.h"
 #include "circ_elem_array.h"
@@ -98,7 +97,7 @@ public:
 
     template <typename F>
     static queue* multi_wait_for(F&& upd) noexcept {
-        for (unsigned k = 0;; ++k) {
+        while (1) {
             auto [ques, size] = upd();
             for (std::size_t i = 0; i < static_cast<std::size_t>(size); ++i) {
                 queue* que = ques[i];
@@ -108,9 +107,7 @@ public:
                     return que;
                 }
             }
-            if (k < 1024) std::this_thread::yield();
-            // yielding => sleeping
-            else std::this_thread::sleep_for(std::chrono::milliseconds(1));
+            std::this_thread::yield();
         }
     }
 
diff --git a/src/ipc.cpp b/src/ipc.cpp
index 409cbe3..399cb19 100644
--- a/src/ipc.cpp
+++ b/src/ipc.cpp
@@ -1,6 +1,5 @@
 #include "ipc.h"
 
-#include <unordered_map>
 #include <type_traits>
 #include <cstring>
 #include <algorithm>
@@ -12,6 +11,8 @@
 #include "shm.h"
 #include "tls_pointer.h"
 
+#include "memory/resource.hpp"
+
 namespace {
 
 using namespace ipc;
@@ -55,7 +56,7 @@ inline auto& recv_cache() {
              https://developercommunity.visualstudio.com/content/problem/124121/thread-local-variables-fail-to-be-initialized-when.html
              https://software.intel.com/en-us/forums/intel-c-compiler/topic/684827
     */
-    static tls::pointer<std::unordered_map<msg_id_t, buff_t>> rc;
+    static tls::pointer<memory::unordered_map<msg_id_t, buff_t>> rc;
     return *rc.create();
 }
 
diff --git a/src/memory/alloc.hpp b/src/memory/alloc.hpp
new file mode 100644
index 0000000..fc6a845
--- /dev/null
+++ b/src/memory/alloc.hpp
@@ -0,0 +1,171 @@
+#pragma once
+
+#include <limits>
+#include <algorithm>
+#include <cstdlib>
+
+#include "def.h"
+
+namespace ipc {
+namespace memory {
+
+struct static_alloc {
+    static constexpr std::size_t remain() {
+        return (std::numeric_limits<std::size_t>::max)();
+    }
+
+    static constexpr void clear() {}
+
+    static void* alloc(std::size_t size) {
+        return size ? std::malloc(size) : nullptr;
+    }
+
+    static void free(void* p) {
+        std::free(p);
+    }
+
+    static void free(void* p, std::size_t /*size*/) {
+        free(p);
+    }
+};
+
+////////////////////////////////////////////////////////////////
+/// Scope allocation -- The destructor will release all allocated blocks.
+////////////////////////////////////////////////////////////////
+
+template <typename AllocP = static_alloc>
+class scope_alloc {
+public:
+    using alloc_policy = AllocP;
+
+private:
+    alloc_policy alloc_;
+
+    struct block_t {
+        block_t* next_;
+    };
+    block_t* list_ = nullptr;
+
+public:
+    scope_alloc() = default;
+
+    scope_alloc(scope_alloc&& rhs)            { this->swap(rhs); }
+    scope_alloc& operator=(scope_alloc&& rhs) { this->swap(rhs); return (*this); }
+
+    ~scope_alloc() { clear(); }
+
+public:
+    void swap(scope_alloc& rhs) {
+        std::swap(this->alloc_, rhs.alloc_);
+        std::swap(this->list_ , rhs.list_);
+    }
+
+    std::size_t remain() const {
+        std::size_t c = 0;
+        auto curr = list_;
+        while (curr != nullptr) {
+            ++c;
+            curr = curr->next_;
+        }
+        return c;
+    }
+
+    void clear() {
+        while (list_ != nullptr) {
+            auto curr = list_;
+            list_ = list_->next_;
+            alloc_.free(curr);
+        }
+        // now list_ is nullptr
+        alloc_.clear();
+    }
+
+    void* alloc(std::size_t size) {
+        auto curr = static_cast<block_t*>(alloc_.alloc(sizeof(block_t) + size));
+        curr->next_ = list_;
+        return ((list_ = curr) + 1);
+    }
+
+    void free(void* /*p*/) {}
+};
+
+////////////////////////////////////////////////////////////////
+/// Fixed-size blocks allocation
+////////////////////////////////////////////////////////////////
+
+template <std::size_t BlockSize, typename AllocP = scope_alloc<>>
+class fixed_pool {
+public:
+    using alloc_policy = AllocP;
+
+    enum : std::size_t {
+        block_size = (std::max)(BlockSize, sizeof(void*))
+    };
+
+private:
+    alloc_policy alloc_;
+    std::size_t init_expand_, iter_;
+    void*  cursor_;
+
+    void expand() {
+        void** p = reinterpret_cast<void**>(cursor_ = alloc_.alloc(block_size * iter_));
+        for (std::size_t i = 0; i < iter_ - 1; ++i)
+            p = reinterpret_cast<void**>((*p) = reinterpret_cast<byte_t*>(p) + block_size);
+        (*p) = nullptr;
+        iter_ *= 2;
+    }
+
+    void init(std::size_t init_expand) {
+        iter_ = init_expand_ = init_expand;
+        cursor_ = nullptr;
+    }
+
+public:
+    explicit fixed_pool(std::size_t init_expand = 1) {
+        init(init_expand);
+    }
+
+    fixed_pool(fixed_pool&& rhs)            { this->swap(rhs); }
+    fixed_pool& operator=(fixed_pool&& rhs) { this->swap(rhs); return (*this); }
+
+    ~fixed_pool() { clear(); }
+
+public:
+    void swap(fixed_pool& rhs) {
+        std::swap(this->alloc_      , rhs.alloc_);
+        std::swap(this->init_expand_, rhs.init_expand_);
+        std::swap(this->iter_       , rhs.iter_);
+        std::swap(this->cursor_     , rhs.cursor_);
+    }
+
+    std::size_t remain() const {
+        std::size_t c = 0;
+        void* curr = cursor_;
+        while (curr != nullptr) {
+            ++c;
+            curr = *reinterpret_cast<void**>(curr); // curr = next
+        }
+        return c * block_size;
+    }
+
+    void clear() {
+        alloc_.clear();
+        init(init_expand_);
+    }
+
+    void* alloc() {
+        if (cursor_ == nullptr) expand();
+        void* p = cursor_;
+        cursor_ = *reinterpret_cast<void**>(p);
+        return p;
+    }
+
+    void free(void* p) {
+        if (p == nullptr) return;
+        *reinterpret_cast<void**>(p) = cursor_;
+        cursor_ = p;
+    }
+};
+
+} // namespace memory
+} // namespace ipc
diff --git a/src/memory/resource.hpp b/src/memory/resource.hpp
new file mode 100644
index 0000000..43b29bb
--- /dev/null
+++ b/src/memory/resource.hpp
@@ -0,0 +1,85 @@
+#pragma once
+
+#include <type_traits>
+#include <initializer_list>
+#include <limits>
+#include <utility>
+#include <functional>
+#include <unordered_map>
+
+#include "tls_pointer.h"
+
+#include "memory/alloc.hpp"
+#include "memory/wrapper.hpp"
+
+namespace ipc {
+namespace memory {
+
+namespace detail {
+
+template <typename Comp, typename F, std::size_t...I>
+void switch_constexpr(std::size_t i, std::index_sequence<I...>, F&& f) {
+    [[maybe_unused]] std::initializer_list<int> expand {
+        (Comp{}(i, I) && (f(std::integral_constant<size_t, I>{}), 0))...
+    };
+}
+
+} // namespace detail
+
+class pool_alloc {
+private:
+    template <std::size_t Size>
+    static auto& fixed() {
+        static tls::pointer<fixed_pool<Size>> fp;
+        return *fp.create();
+    }
+
+    template <typename F>
+    static void choose(std::size_t size, F&& f) {
+        enum : std::size_t { base_size = sizeof(void*) };
+        detail::switch_constexpr<std::less_equal<std::size_t>>(size, std::index_sequence<
+            base_size     , base_size * 2 ,
+            base_size * 4 , base_size * 6 ,
+            base_size * 8 , base_size * 12,
+            base_size * 16, base_size * 20,
+            base_size * 24, base_size * 28,
+            base_size * 32, base_size * 40,
+            base_size * 48, base_size * 56,
+            base_size * 64
+        >{}, [&f](auto index) { f(fixed<decltype(index)::value>()); });
+    }
+
+public:
+    pool_alloc() = default;
+    pool_alloc(const pool_alloc&) = default;
+    pool_alloc& operator=(const pool_alloc&) = default;
+    pool_alloc(pool_alloc&&) = default;
+    pool_alloc& operator=(pool_alloc&&) = default;
+
+    static constexpr std::size_t remain() {
+        return (std::numeric_limits<std::size_t>::max)();
+    }
+
+    static constexpr void clear() {}
+
+    static void* alloc(std::size_t size) {
+        void* p;
+        choose(size, [&p](auto& fp) { p = fp.alloc(); });
+        return p;
+    }
+
+    static void free(void* p, std::size_t size) {
+        choose(size, [p](auto& fp) { fp.free(p); });
+    }
+};
+
+template <typename T>
+using allocator = allocator_wrapper<T, pool_alloc>;
+
+template<typename Key, typename T>
+using unordered_map = std::unordered_map<
+    Key, T//, std::hash<Key>, std::equal_to<Key>, allocator<std::pair<const Key, T>>
+>;
+
+} // namespace memory
+} // namespace ipc
diff --git a/src/memory/wrapper.hpp b/src/memory/wrapper.hpp
new file mode 100644
index 0000000..f8a07c5
--- /dev/null
+++ b/src/memory/wrapper.hpp
@@ -0,0 +1,110 @@
+#pragma once
+
+#include <utility>
+#include <limits>
+#include <new>
+
+namespace ipc {
+namespace memory {
+
+////////////////////////////////////////////////////////////////
+/// The allocator wrapper class
+////////////////////////////////////////////////////////////////
+
+template <typename T, typename AllocP>
+class allocator_wrapper {
+
+    template <typename U, typename AllocU>
+    friend class allocator_wrapper;
+
+public:
+    // type definitions
+    typedef T                 value_type;
+    typedef value_type*       pointer;
+    typedef const value_type* const_pointer;
+    typedef value_type&       reference;
+    typedef const value_type& const_reference;
+    typedef std::size_t       size_type;
+    typedef AllocP            alloc_policy;
+
+private:
+    alloc_policy alloc_;
+
+public:
+    allocator_wrapper(void) noexcept = default;
+
+    allocator_wrapper(const allocator_wrapper<T, AllocP>& rhs) noexcept
+        : alloc_(rhs.alloc_)
+    {}
+
+    template <typename U>
+    allocator_wrapper(const allocator_wrapper<U, AllocP>& rhs) noexcept
+        : alloc_(rhs.alloc_)
+    {}
+
+    allocator_wrapper(allocator_wrapper<T, AllocP>&& rhs) noexcept
+        : alloc_(std::move(rhs.alloc_))
+    {}
+
+    template <typename U>
+    allocator_wrapper(allocator_wrapper<U, AllocP>&& rhs) noexcept
+        : alloc_(std::move(rhs.alloc_))
+    {}
+
+    allocator_wrapper(const AllocP& rhs) noexcept
+        : alloc_(rhs)
+    {}
+
+    allocator_wrapper(AllocP&& rhs) noexcept
+        : alloc_(std::move(rhs))
+    {}
+
+public:
+    // the other type of std_allocator
+    template <typename U>
+    struct rebind { typedef allocator_wrapper<U, AllocP> other; };
+
+    constexpr size_type max_size(void) const noexcept {
+        return (std::numeric_limits<size_type>::max)() / sizeof(T);
+    }
+
+public:
+    pointer allocate(size_type count) noexcept {
+        if (count == 0) return nullptr;
+        if (count > this->max_size()) return nullptr;
+        return static_cast<pointer>(alloc_.alloc(count * sizeof(T)));
+    }
+
+    void deallocate(pointer p, size_type count) {
+        alloc_.free(p, count * sizeof(T));
+    }
+
+    template <typename... P>
+    static void construct(pointer p, P&&... params) {
+        ::new (static_cast<void*>(p)) T(std::forward<P>(params)...);
+    }
+
+    static void destroy(pointer p) {
+        p->~T();
+    }
+};
+
+template <class AllocP>
+class allocator_wrapper<void, AllocP> {
+public:
+    typedef void    value_type;
+    typedef AllocP  alloc_policy;
+};
+
+template <typename T, typename U, class AllocP>
+constexpr bool operator==(const allocator_wrapper<T, AllocP>&, const allocator_wrapper<U, AllocP>&) noexcept {
+    return true;
+}
+
+template <typename T, typename U, class AllocP>
+constexpr bool operator!=(const allocator_wrapper<T, AllocP>&, const allocator_wrapper<U, AllocP>&) noexcept {
+    return false;
+}
+
+} // namespace memory
+} // namespace ipc
diff --git a/src/platform/shm_linux.cpp b/src/platform/shm_linux.cpp
index fac43d4..13d47e5 100644
--- a/src/platform/shm_linux.cpp
+++ b/src/platform/shm_linux.cpp
@@ -6,11 +6,11 @@
 #include <unistd.h>
 #include <fcntl.h>
 
-#include <unordered_map>
 #include <atomic>
 #include <string>
 
 #include "tls_pointer.h"
+#include "memory/resource.hpp"
 
 namespace {
 
@@ -25,7 +25,7 @@ constexpr void* mem_of(void* mem) {
 }
 
 inline auto& m2h() {
-    static ipc::tls::pointer<std::unordered_map<void*, std::string>> cache;
+    static ipc::tls::pointer<ipc::memory::unordered_map<void*, std::string>> cache;
     return *cache.create();
 }
 
diff --git a/src/platform/shm_win.cpp b/src/platform/shm_win.cpp
index b555842..130102f 100644
--- a/src/platform/shm_win.cpp
+++ b/src/platform/shm_win.cpp
@@ -7,10 +7,10 @@
 #include <locale>
 #include <codecvt>
 #include <utility>
-#include <unordered_map>
 
 #include "def.h"
 #include "tls_pointer.h"
+#include "memory/resource.hpp"
 
 namespace {
 
@@ -28,7 +28,7 @@ constexpr auto to_tchar(std::string && str) -> IsSame<T, std::wstring> {
 }
 
 inline auto& m2h() {
-    static ipc::tls::pointer<std::unordered_map<void*, HANDLE>> cache;
+    static ipc::tls::pointer<ipc::memory::unordered_map<void*, HANDLE>> cache;
     return *cache.create();
 }
 
diff --git a/test/test_ipc.cpp b/test/test_ipc.cpp
index 77480fc..0447fd5 100644
--- a/test/test_ipc.cpp
+++ b/test/test_ipc.cpp
@@ -304,10 +304,10 @@ void test_lock_performance() {
 }
 
 void Unit::test_rw_lock() {
-    test_lock_performance<1, 1>();
-    test_lock_performance<4, 4>();
-    test_lock_performance<1, 8>();
-    test_lock_performance<8, 1>();
+//    test_lock_performance<1, 1>();
+//    test_lock_performance<4, 4>();
+//    test_lock_performance<1, 8>();
+//    test_lock_performance<8, 1>();
 }
 
 void Unit::test_send_recv() {