A server application system includes a server application module that performs predetermined functions in response to external user requests. The server application system further includes a characterization module coupled to receive the external user requests, and to determine a threshold for user tolerance of delay for each of the user requests. Tolerance threshold is calculated using task type, service level, and session duration. A classification module is then coupled to the characterization module to dynamically assign each of the user requests an allowable processing deadline based on the corresponding user tolerance threshold of that user request. The processing deadline specifies the time period within which the particular user request must be serviced by the server application module. A method of admitting incoming user requests to a server application is also described.