Methods and systems are provided for determining performance characteristics of an application processing system. The method comprises monitoring throughput of a plurality of resources of the system in a selected time window. A change rate is detected in the throughput of the resources, respectively, representative of a change to constancy of workload in at least some of the resources. Such a change in constancy comprises a knee point of a plot of resource usage comprising load relative to throughput. The time of the change rate is identified within the time window. A relatively first to occur of a plurality of resources knee points is determined wherein the resource corresponding to the first to occur is determined to have a fully loaded throughput within the multi-tier processing system. The determination of the first to occur knee point comprises pinpointing a bottleneck starting point within the application processing system.