If you're running Liberty, take the extra step and assign WLM transaction classes to your HTTP requests. WLM will use enclaves to track and manage threads across different address spaces and give you the total GCP and zIIP time consumed. You also get enhanced WLM goal management and reporting, including a new value called the response time ratio that tells you how this particular request did compared to the goal for the service class for which the work was classified. You need to enable the WLM feature and configure classification rules, but it is well worth the effort!