The following list includes the key points to remember when monitoring threads:
- If the web server is running in worker process isolation mode, monitor the W3wp instance.
- It can be difficult to balance the number of threads against overall performance as measured by connections and requests. When tuning threads, follow up with overall performance monitoring to see whether performance increases or decreases.
- Chart the Process\Thread Count: W3wp value over time to see how many threads the worker process creates and how the number of threads varies. Then observe the processor time for each thread in the process (Thread% Processor Time: W3wp/Thread #) during periods of high, medium, and low server activity (as indicated by the other performance measures).
- To determine whether the thread count needs to be adjusted, compare the number of threads and the processor time for each thread in the process to the total processor time. If the threads are constantly busy, but are not fully using the processor time, performance might be improved by allowing more threads. However, if all of the threads are busy and the processors are operating at close to their maximum capacity, it is best to distribute the load across more servers instead of increasing the number of threads.
For detailed information about monitoring threads in IIS, see