diff --git a/sf-stream/include/ZmqPulseSyncReceiver.hpp b/sf-stream/include/ZmqPulseSyncReceiver.hpp
index aa00035..624de34 100644
--- a/sf-stream/include/ZmqPulseSyncReceiver.hpp
+++ b/sf-stream/include/ZmqPulseSyncReceiver.hpp
@@ -8,6 +8,11 @@
 
 #include "formats.hpp"
 
+struct PulseAndSync {
+    const uint64_t pulse_id;
+    const uint32_t n_lost_pulses;
+};
+
 class ZmqPulseSyncReceiver {
 
     void* ctx_;
@@ -22,7 +27,7 @@ public:
             const int n_modules);
     ~ZmqPulseSyncReceiver();
 
-    uint64_t get_next_pulse_id() const;
+    PulseAndSync get_next_pulse_id() const;
 };
 
 
diff --git a/sf-stream/src/ZmqPulseSyncReceiver.cpp b/sf-stream/src/ZmqPulseSyncReceiver.cpp
index f309389..ead65ee 100644
--- a/sf-stream/src/ZmqPulseSyncReceiver.cpp
+++ b/sf-stream/src/ZmqPulseSyncReceiver.cpp
@@ -38,7 +38,7 @@ ZmqPulseSyncReceiver::~ZmqPulseSyncReceiver()
     }
 }
 
-uint64_t ZmqPulseSyncReceiver::get_next_pulse_id() const
+PulseAndSync ZmqPulseSyncReceiver::get_next_pulse_id() const
 {
     uint64_t pulses[n_modules_];
 
@@ -52,12 +52,12 @@ uint64_t ZmqPulseSyncReceiver::get_next_pulse_id() const
     }
 
     if (modules_in_sync) {
-        return pulses[0];
+        return {pulses[0], 0};
     }
 
+    // How many pulses we lost in total to get the next pulse_id.
+    uint32_t n_lost_pulses = 0;
     for (int i_sync=0; i_sync < SYNC_RETRY_LIMIT; i_sync++) {
-        cout << "Sync attempt " << i_sync << endl;
-
         uint64_t min_pulse_id = numeric_limits<uint64_t>::max();;
         uint64_t max_pulse_id = 0;
 
@@ -83,18 +83,26 @@ uint64_t ZmqPulseSyncReceiver::get_next_pulse_id() const
         }
 
         modules_in_sync = true;
+        // Max pulses we lost in this sync attempt.
+        uint32_t i_sync_lost_pulses = 0;
         for (int i = 0; i < n_modules_; i++) {
+            // How many pulses we lost for this specific module.
+            uint32_t i_module_lost_pulses = 0;
             while (pulses[i] < max_pulse_id) {
                 zmq_recv(sockets_[i], &pulses[i], sizeof(uint64_t), 0);
+                i_module_lost_pulses++;
             }
 
+            i_sync_lost_pulses = max(i_sync_lost_pulses, i_module_lost_pulses);
+
             if (pulses[i] != max_pulse_id) {
                 modules_in_sync = false;
             }
         }
+        n_lost_pulses += i_sync_lost_pulses;
 
         if (modules_in_sync) {
-            return pulses[0];
+            return {pulses[0], n_lost_pulses};
         }
     }