Workload is programmatically distributed across a set of execution resources. In a multithreaded server environment, response time to end users is improved while increasing the efficiency of software execution and resource usage. Execution time and wait/queued time are tracked, for various types of requests being serviced by a server. Multiple logical pools of threads are used to service these requests, and inbound requests are directed to a selected one of these pools such that requests of similar execution-time requirements are serviced by the threads in that pool. The number and size of thread pools may be adjusted programmatically, and the distribution calculation (i.e., determining which inbound requests should be assigned to which pools) is a programmatic determination. In preferred embodiments, only one of these variables is adjusted at a time, and the results are monitored to determine whether the effect was positive or negative. The disclosed techniques also apply to tracking and classifying requests by method name (and, optionally, parameters).