Does your workflow take a long time to run? The Enable Performance Profiling function will help you to narrow down which pesky tool (or tools) are taking the longest to run!
Click in the white space of your workflow to review the Configuration pane on the left-hand side.
Click on the Runtime tab.
Then check the box for Enable Performance Profiling.
Run your workflow.
Your results pane will now display a running time for each tool and it will display a percentage of the entire process next to the tool.