diff --git a/include/circ_elem_array.h b/include/circ_elem_array.h
index 9984fba..4923ad4 100644
--- a/include/circ_elem_array.h
+++ b/include/circ_elem_array.h
@@ -125,7 +125,7 @@ struct prod_cons<relat::multi, relat::multi, trans::unicast>
     template <typename E, typename F, std::size_t S>
     bool push(E* /*elems*/, F&& f, detail::elem_t<S>* elem_start) {
         detail::u2_t cur_ct, nxt_ct;
-        for (unsigned k = 0;;) {
+        while(1) {
             cur_ct = ct_.load(std::memory_order_acquire);
             if (detail::index_of(nxt_ct = cur_ct + 1) ==
                 detail::index_of(rd_.load(std::memory_order_relaxed))) {
@@ -134,15 +134,15 @@ struct prod_cons<relat::multi, relat::multi, trans::unicast>
             if (ct_.compare_exchange_weak(cur_ct, nxt_ct, std::memory_order_relaxed)) {
                 break;
             }
-            ipc::sleep(k);
+            std::this_thread::yield();
         }
         std::forward<F>(f)(elem_start + detail::index_of(cur_ct));
-        for (unsigned k = 0;;) {
+        while(1) {
             auto exp_wt = cur_ct;
             if (wt_.compare_exchange_weak(exp_wt, nxt_ct, std::memory_order_release)) {
                 break;
             }
-            ipc::sleep(k);
+            std::this_thread::yield();
         }
         return true;
     }
@@ -171,13 +171,13 @@ struct prod_cons<relat::single, relat::multi, trans::broadcast> {
         if (conn_cnt == 0) return false;
         auto el = elem_start + detail::index_of(wt_.load(std::memory_order_relaxed));
         // check all consumers have finished reading this element
-        for (unsigned k = 0;;) {
+        while(1) {
             rc_t expected = 0;
             if (el->head_.rc_.compare_exchange_weak(
                         expected, static_cast<rc_t>(conn_cnt), std::memory_order_relaxed)) {
                 break;
             }
-            ipc::sleep(k);
+            std::this_thread::yield();
             conn_cnt = elems->conn_count(); // acquire
             if (conn_cnt == 0) return false;
         }
@@ -205,6 +205,42 @@ struct prod_cons<relat::single, relat::multi, trans::broadcast> {
     }
 };
 
+template <>
+struct prod_cons<relat::multi, relat::multi, trans::broadcast>
+     : prod_cons<relat::single, relat::multi, trans::broadcast> {
+
+    std::atomic<detail::u2_t> ct_ { 0 }; // commit index
+
+    template <typename E, typename F, std::size_t S>
+    bool push(E* elems, F&& f, detail::elem_t<S>* elem_start) {
+        auto conn_cnt = elems->conn_count(); // acquire
+        if (conn_cnt == 0) return false;
+        detail::u2_t cur_ct = ct_.fetch_add(1, std::memory_order_relaxed),
+                     nxt_ct = cur_ct + 1;
+        auto el = elem_start + detail::index_of(cur_ct);
+        // check all consumers have finished reading this element
+        while(1) {
+            rc_t expected = 0;
+            if (el->head_.rc_.compare_exchange_weak(
+                        expected, static_cast<rc_t>(conn_cnt), std::memory_order_relaxed)) {
+                break;
+            }
+            std::this_thread::yield();
+            conn_cnt = elems->conn_count(); // acquire
+            if (conn_cnt == 0) return false;
+        }
+        std::forward<F>(f)(el->data_);
+        while(1) {
+            auto exp_wt = cur_ct;
+            if (wt_.compare_exchange_weak(exp_wt, nxt_ct, std::memory_order_release)) {
+                break;
+            }
+            std::this_thread::yield();
+        }
+        return true;
+    }
+};
+
 ////////////////////////////////////////////////////////////////
 /// element-array implementation
 ////////////////////////////////////////////////////////////////
diff --git a/include/rw_lock.h b/include/rw_lock.h
index 92c6fbc..8e7184a 100644
--- a/include/rw_lock.h
+++ b/include/rw_lock.h
@@ -57,7 +57,19 @@
 
 namespace ipc {
 
-template <std::size_t N = 8192, typename K>
+template <typename K>
+inline void yield(K& k) noexcept {
+    if (k < 4)  { /* Do nothing */ }
+    else
+    if (k < 16) { IPC_LOCK_PAUSE_(); }
+    else {
+        std::this_thread::yield();
+        return;
+    }
+    ++k;
+}
+
+template <std::size_t N = 4096, typename K>
 inline void sleep(K& k) noexcept {
     if (k < static_cast<K>(N)) {
         std::this_thread::yield();
@@ -69,18 +81,6 @@ inline void sleep(K& k) noexcept {
     ++k;
 }
 
-template <std::size_t N = 32, typename K>
-inline void yield(K& k) noexcept {
-    if (k < 4)  { /* Do nothing */ }
-    else
-    if (k < 16) { IPC_LOCK_PAUSE_(); }
-    else {
-        ipc::sleep<N>(k);
-        return;
-    }
-    ++k;
-}
-
 } // namespace ipc
 
 #pragma pop_macro("IPC_LOCK_PAUSE_")
diff --git a/test/test_circ.cpp b/test/test_circ.cpp
index 1cf1995..0fe66b6 100644
--- a/test/test_circ.cpp
+++ b/test/test_circ.cpp
@@ -266,29 +266,39 @@ void Unit::test_prod_cons_1v1() {
         ipc::circ::prod_cons<ipc::circ::relat::single,
                              ipc::circ::relat::single,
                              ipc::circ::trans::unicast>
-    > el_arr_ss;
-    benchmark_prod_cons<1, 1, LoopCount, cq_t>(&el_arr_ss);
-    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_ss);
+    > el_arr_ssu;
+    benchmark_prod_cons<1, 1, LoopCount, cq_t>(&el_arr_ssu);
+    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_ssu);
 
     ipc::circ::elem_array<
         sizeof(msg_t),
         ipc::circ::prod_cons<ipc::circ::relat::single,
                              ipc::circ::relat::multi,
                              ipc::circ::trans::unicast>
-    > el_arr_smn;
-    benchmark_prod_cons<1, 1, LoopCount, decltype(el_arr_smn)::policy_t>(&el_arr_smn);
-    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_smn);
+    > el_arr_smu;
+    benchmark_prod_cons<1, 1, LoopCount, decltype(el_arr_smu)::policy_t>(&el_arr_smu);
+    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_smu);
 
     ipc::circ::elem_array<
         sizeof(msg_t),
         ipc::circ::prod_cons<ipc::circ::relat::multi,
                              ipc::circ::relat::multi,
                              ipc::circ::trans::unicast>
-    > el_arr_mmn;
-    benchmark_prod_cons<1, 1, LoopCount, decltype(el_arr_mmn)::policy_t>(&el_arr_mmn);
-    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_mmn);
+    > el_arr_mmu;
+    benchmark_prod_cons<1, 1, LoopCount, decltype(el_arr_mmu)::policy_t>(&el_arr_mmu);
+    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_mmu);
 
     test_prod_cons<1, 1>();
+    test_prod_cons<1, 1, false>();
+
+    ipc::circ::elem_array<
+        sizeof(msg_t),
+        ipc::circ::prod_cons<ipc::circ::relat::multi,
+                             ipc::circ::relat::multi,
+                             ipc::circ::trans::broadcast>
+    > el_arr_mmb;
+    benchmark_prod_cons<1, 1, LoopCount, cq_t>(&el_arr_mmb);
+    benchmark_prod_cons<1, 1, LoopCount, void>(&el_arr_mmb);
 }
 
 void Unit::test_prod_cons_1v3() {
@@ -297,20 +307,30 @@ void Unit::test_prod_cons_1v3() {
         ipc::circ::prod_cons<ipc::circ::relat::single,
                              ipc::circ::relat::multi,
                              ipc::circ::trans::unicast>
-    > el_arr_smn;
-    benchmark_prod_cons<1, 3, LoopCount, decltype(el_arr_smn)::policy_t>(&el_arr_smn);
-    benchmark_prod_cons<1, 3, LoopCount, void>(&el_arr_smn);
+    > el_arr_smu;
+    benchmark_prod_cons<1, 3, LoopCount, decltype(el_arr_smu)::policy_t>(&el_arr_smu);
+    benchmark_prod_cons<1, 3, LoopCount, void>(&el_arr_smu);
 
     ipc::circ::elem_array<
         sizeof(msg_t),
         ipc::circ::prod_cons<ipc::circ::relat::multi,
                              ipc::circ::relat::multi,
                              ipc::circ::trans::unicast>
-    > el_arr_mmn;
-    benchmark_prod_cons<1, 3, LoopCount, decltype(el_arr_mmn)::policy_t>(&el_arr_mmn);
-    benchmark_prod_cons<1, 3, LoopCount, void>(&el_arr_mmn);
+    > el_arr_mmu;
+    benchmark_prod_cons<1, 3, LoopCount, decltype(el_arr_mmu)::policy_t>(&el_arr_mmu);
+    benchmark_prod_cons<1, 3, LoopCount, void>(&el_arr_mmu);
 
     test_prod_cons<1, 3>();
+    test_prod_cons<1, 3, false>();
+
+    ipc::circ::elem_array<
+        sizeof(msg_t),
+        ipc::circ::prod_cons<ipc::circ::relat::multi,
+                             ipc::circ::relat::multi,
+                             ipc::circ::trans::broadcast>
+    > el_arr_mmb;
+    benchmark_prod_cons<1, 3, LoopCount, cq_t>(&el_arr_mmb);
+    benchmark_prod_cons<1, 3, LoopCount, void>(&el_arr_mmb);
 }
 
 void Unit::test_prod_cons_performance() {
@@ -319,31 +339,47 @@ void Unit::test_prod_cons_performance() {
         ipc::circ::prod_cons<ipc::circ::relat::single,
                              ipc::circ::relat::multi,
                              ipc::circ::trans::unicast>
-    > el_arr_smn;
-    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_smn](auto index) {
-        benchmark_prod_cons<1, decltype(index)::value + 1, LoopCount, void>(&el_arr_smn);
-    });
-
-    ipc::circ::elem_array<
-        sizeof(msg_t),
-        ipc::circ::prod_cons<ipc::circ::relat::multi,
-                             ipc::circ::relat::multi,
-                             ipc::circ::trans::unicast>
-    > el_arr_mmn;
-    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmn](auto index) {
-        benchmark_prod_cons<1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmn);
-    });
-    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmn](auto index) {
-        benchmark_prod_cons<decltype(index)::value + 1, 1, LoopCount, void>(&el_arr_mmn);
-    });
-    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmn](auto index) {
-        benchmark_prod_cons<decltype(index)::value + 1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmn);
+    > el_arr_smu;
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_smu](auto index) {
+        benchmark_prod_cons<1, decltype(index)::value + 1, LoopCount, void>(&el_arr_smu);
     });
 
     ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [](auto index) {
         test_prod_cons<1, decltype(index)::value + 1, false>();
     });
     test_prod_cons<1, 10>(); // test & verify
+
+    ipc::circ::elem_array<
+        sizeof(msg_t),
+        ipc::circ::prod_cons<ipc::circ::relat::multi,
+                             ipc::circ::relat::multi,
+                             ipc::circ::trans::unicast>
+    > el_arr_mmu;
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmu](auto index) {
+        benchmark_prod_cons<1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmu);
+    });
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmu](auto index) {
+        benchmark_prod_cons<decltype(index)::value + 1, 1, LoopCount, void>(&el_arr_mmu);
+    });
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmu](auto index) {
+        benchmark_prod_cons<decltype(index)::value + 1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmu);
+    });
+
+    ipc::circ::elem_array<
+        sizeof(msg_t),
+        ipc::circ::prod_cons<ipc::circ::relat::multi,
+                             ipc::circ::relat::multi,
+                             ipc::circ::trans::broadcast>
+    > el_arr_mmb;
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmb](auto index) {
+        benchmark_prod_cons<1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmb);
+    });
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmb](auto index) {
+        benchmark_prod_cons<decltype(index)::value + 1, 1, LoopCount, void>(&el_arr_mmb);
+    });
+    ipc::mem::detail::static_for(std::make_index_sequence<10>{}, [&el_arr_mmb](auto index) {
+        benchmark_prod_cons<decltype(index)::value + 1, decltype(index)::value + 1, LoopCount, void>(&el_arr_mmb);
+    });
 }
 
 void Unit::test_queue() {