diff --git a/src/main/java/teetime/framework/concurrent/WorkerThread.java b/src/main/java/teetime/framework/concurrent/WorkerThread.java
index feb78b689bf9106f08b0a8673bc64d5721469f30..ca1e5e77d0dbc35b7806b0017f36060cc2076880 100644
--- a/src/main/java/teetime/framework/concurrent/WorkerThread.java
+++ b/src/main/java/teetime/framework/concurrent/WorkerThread.java
@@ -73,7 +73,7 @@ public class WorkerThread extends Thread {
 			// beforeStageExecutionStopWatch.end();
 
 			this.startStageExecution(stage);
-			// stageExecutionStopWatch.start(); // expensive: takes 1/3 of overall time
+			// stageExecutionStopWatch.start();
 			final boolean executedSuccessfully = stage.execute();
 			// stageExecutionStopWatch.end();
 			this.finishStageExecution(stage, executedSuccessfully);
diff --git a/src/main/java/teetime/framework/core/AbstractFilter.java b/src/main/java/teetime/framework/core/AbstractFilter.java
index 83b6b9895c6a7263cfda7708b150c508b54c263c..16b7cabb94383b09e2ea493352f70d7d40330841 100644
--- a/src/main/java/teetime/framework/core/AbstractFilter.java
+++ b/src/main/java/teetime/framework/core/AbstractFilter.java
@@ -178,7 +178,7 @@ public abstract class AbstractFilter<S extends IStage> extends AbstractStage imp
 	@Override
 	public void onPortIsClosed(final IInputPort<S, ?> inputPort) {
 		// inputPort.setState(IInputPort.State.CLOSING);
-		this.enabledInputPorts--;
+		this.enabledInputPorts--;	// FIXME not thread-safe
 		// this.logger.info("Closed " + "(" + this.enabledInputPorts + " remaining) " + inputPort + " of " + this);
 
 		if (this.enabledInputPorts < 0) {