mvn exec:java -Dexec.classpathScope=test -Dexec.mainClass="org.eclipse.jetty.quickstart.StartBenchmarkWar"

OR

mvn exec:java -Dexec.classpathScope=test -Dexec.mainClass="org.eclipse.jetty.quickstart.PreconfigureBenchmarkWar"
mvn exec:java -Dexec.classpathScope=test -Dexec.mainClass="org.eclipse.jetty.quickstart.QuickStartBenchmarkWar"