diff --git a/dataflow_cpp/include/embb/dataflow/internal/process.h b/dataflow_cpp/include/embb/dataflow/internal/process.h
index b71cbc7..ca201a7 100644
--- a/dataflow_cpp/include/embb/dataflow/internal/process.h
+++ b/dataflow_cpp/include/embb/dataflow/internal/process.h
@@ -55,7 +55,7 @@ class Process< Slices, Serial, Inputs<Slices, I1, I2, I3, I4, I5>,
 
   explicit Process(FunctionType function)
     : executor_(function) {
-    input_clock_expected_ = 0;
+    next_clock_ = 0;
     inputs_.SetListener(this);
   }
 
@@ -68,16 +68,7 @@ class Process< Slices, Serial, Inputs<Slices, I1, I2, I3, I4, I5>,
   }
 
   virtual void Run(int clock) {
-    bool ordered = Serial;
-    if (ordered) {
-      // force ordering
-      while (input_clock_expected_ != clock) embb::base::Thread::CurrentYield();
-    }
-
     executor_.Execute(clock, inputs_, outputs_);
-    //inputs_.Clear(clock);
-
-    input_clock_expected_ = clock + 1;
   }
 
   InputsType & GetInputs() {
@@ -104,20 +95,35 @@ class Process< Slices, Serial, Inputs<Slices, I1, I2, I3, I4, I5>,
   }
 
   virtual void OnClock(int clock) {
-    const int idx = clock % Slices;
     if (!inputs_.AreAtClock(clock))
       EMBB_THROW(embb::base::ErrorException,
         "Some inputs are not at expected clock.")
-    action_[idx] = Action(this, clock);
-    sched_->Spawn(action_[idx]);
+
+    bool ordered = Serial;
+    if (ordered) {
+      lock_.Lock();
+      for (int ii = next_clock_; ii < next_clock_ + Slices; ii++) {
+        if (!inputs_.AreAtClock(ii)) {
+          break;
+        }
+        next_clock_ = ii + 1;
+        Run(ii);
+      }
+      lock_.Unlock();
+    } else {
+      const int idx = clock % Slices;
+      action_[idx] = Action(this, clock);
+      sched_->Spawn(action_[idx]);
+    }
   }
 
  private:
   InputsType inputs_;
   OutputsType outputs_;
   ExecutorType executor_;
-  embb::base::Atomic<int> input_clock_expected_;
+  int next_clock_;
   Action action_[Slices];
+  SpinLock lock_;
 };
 
 } // namespace internal
diff --git a/dataflow_cpp/include/embb/dataflow/internal/sink.h b/dataflow_cpp/include/embb/dataflow/internal/sink.h
index f711e11..1dd8278 100644
--- a/dataflow_cpp/include/embb/dataflow/internal/sink.h
+++ b/dataflow_cpp/include/embb/dataflow/internal/sink.h
@@ -51,7 +51,7 @@ class Sink< Slices, Inputs<Slices, I1, I2, I3, I4, I5> >
 
   explicit Sink(FunctionType function)
     : executor_(function) {
-    input_clock_expected_ = 0;
+    next_clock_ = 0;
     inputs_.SetListener(this);
   }
 
@@ -64,17 +64,10 @@ class Sink< Slices, Inputs<Slices, I1, I2, I3, I4, I5> >
   }
 
   virtual void Run(int clock) {
-    //const int idx = clock % Slices;
-
-    // force ordering
-    while (input_clock_expected_ != clock) embb::base::Thread::CurrentYield();
-
     if (inputs_.AreNoneBlank(clock)) {
       executor_.Execute(clock, inputs_);
     }
     listener_->OnClock(clock);
-
-    input_clock_expected_ = clock + 1;
   }
 
   InputsType & GetInputs() {
@@ -87,26 +80,31 @@ class Sink< Slices, Inputs<Slices, I1, I2, I3, I4, I5> >
   }
 
   virtual void OnClock(int clock) {
-    lock_.Lock();
     TrySpawn(clock);
-    lock_.Unlock();
   }
 
  private:
   InputsType inputs_;
   ExecutorType executor_;
-  embb::base::Atomic<int> input_clock_expected_;
+  int next_clock_;
   Action action_[Slices];
   ClockListener * listener_;
   SpinLock lock_;
 
   void TrySpawn(int clock) {
-    const int idx = clock % Slices;
     if (!inputs_.AreAtClock(clock))
       EMBB_THROW(embb::base::ErrorException,
         "Some inputs are not at expected clock.")
-    action_[idx] = Action(this, clock);
-    sched_->Spawn(action_[idx]);
+
+    lock_.Lock();
+    for (int ii = next_clock_; ii < next_clock_ + Slices; ii++) {
+      if (!inputs_.AreAtClock(ii)) {
+        break;
+      }
+      next_clock_ = ii + 1;
+      Run(ii);
+    }
+    lock_.Unlock();
   }
 };
 
diff --git a/dataflow_cpp/include/embb/dataflow/internal/source.h b/dataflow_cpp/include/embb/dataflow/internal/source.h
index 155769a..0ad4784 100644
--- a/dataflow_cpp/include/embb/dataflow/internal/source.h
+++ b/dataflow_cpp/include/embb/dataflow/internal/source.h
@@ -66,11 +66,8 @@ class Source< Slices, Outputs<Slices, O1, O2, O3, O4, O5> >
   }
 
   virtual bool Start(int clock) {
-    while (clock != next_clock_) embb::base::Thread::CurrentYield();
     if (not_done_) {
-      const int idx = clock % Slices;
-      action_[idx] = Action(this, clock);
-      sched_->Spawn(action_[idx]);
+      Run(clock);
     }
     return not_done_;
   }
diff --git a/dataflow_cpp/test/dataflow_cpp_test_simple.cc b/dataflow_cpp/test/dataflow_cpp_test_simple.cc
index db7c241..952ada9 100644
--- a/dataflow_cpp/test/dataflow_cpp_test_simple.cc
+++ b/dataflow_cpp/test/dataflow_cpp_test_simple.cc
@@ -36,7 +36,7 @@
 
 #include <embb/dataflow/dataflow.h>
 
-typedef embb::dataflow::Network<4> MyNetwork;
+typedef embb::dataflow::Network<8> MyNetwork;
 typedef MyNetwork::ConstantSource< int > MyConstantSource;
 typedef MyNetwork::Source< int > MySource;
 typedef MyNetwork::SerialProcess< MyNetwork::Inputs<int>::Type,