preformance improvment when using many data_pool objects

src/damaris/gui/DamarisGUI.py

@@ -588,11 +588,36 @@ class DamarisGUI:
         self.toolbar_pause_button.set_sensitive( True )
         self.toolbar_pause_button.set_active( False )
 
-        # delete old data
+        # delete old data - use efficient cleanup
         data_cleanup_start = time.time()
         self.data = None
-        self.monitor.observe_data_pool( self.data )
-        print(f"DEBUG: Data cleanup took {time.time() - data_cleanup_start:.3f}s")
+        
+        # Modern listener management - only clean up listeners when truly needed
+        if hasattr(self, 'monitor') and self.monitor is not None:
+            # Check if we have significant listener activity
+            needs_full_cleanup = False
+            listener_count = 0
+            
+            if hasattr(self.monitor, 'data_pool') and self.monitor.data_pool is not None:
+                try:
+                    # Count actual listeners instead of just items
+                    with self.monitor.data_pool.__dictlock:
+                        listener_count = len(self.monitor.data_pool.__registered_listeners) if hasattr(self.monitor.data_pool, '__registered_listeners') else 0
+                    needs_full_cleanup = listener_count > 5  # Only full cleanup if many listeners
+                except:
+                    needs_full_cleanup = True
+            
+            if needs_full_cleanup:
+                print(f"Performing full cleanup ({listener_count} listeners)...")
+                self.monitor.observe_data_pool( self.data )
+            else:
+                # Efficient cleanup: just reset references without full listener cleanup
+                print(f"Efficient cleanup ({listener_count} listeners - skipping full cleanup)")
+                if hasattr(self.monitor, 'data_pool'):
+                    # Just set to None - listeners will be garbage collected
+                    self.monitor.data_pool = None
+        
+        print(f"DEBUG: Efficient data cleanup took {time.time() - data_cleanup_start:.3f}s")
 
         # set the text mark for hdf logging
         if self.log.textbuffer.get_mark( "lastdumped" ) is None: