How are IIS7 threads assigned?

Question

I added log4net to my application and can now see the thread Ids of user activities as they navigate through my website. Is there any specific algorithm to how threads assignment happens with IIS7, or is it just a random number assignment (I suspect it's not completely random because my low traffic site show threads mostly in the range 10-30)? Any maximum to the number of threads available? And I notice that my scheduler shows up with a weird threads id -- any reason for this? The scheduler is Quartz.net and the id shows as "Scheduler_Worker-10", and not just a number.

Answer 1

This explains all you need to know.

An Excerpt:

When ASP.NET is hosted on IIS 7.0 in integrated mode, the use of threads is a bit different. First of all, the application-level queues are no more. Their performance was always really bad, there was no hope in fixing this, and so we got rid of them. But perhaps the biggest difference is that in IIS 6.0, or ISAPI mode, ASP.NET restricts the number of threads concurrently executing requests, but in IIS 7.0 integrated mode, ASP.NET restricts the number of concurrently executing requests. The difference only matters when the requests are asynchronous (the request either has an asynchronous handler or a module in the pipeline completes asynchronously). Obviously if the reqeusts are synchronous, then the number of concurrently executing requests is the same as the number of threads concurrently executing requests, but if the requests are asynchronous then these two numbers can be quite different as you could have far more reqeusts than threads.

So basically, if requests are synchronous, the same number of threads per request. See here for various parameters.