Scaling up limits of a single IIS worker process

Question

How many cores can a single worker process typically handle before performance becomes impacted?

In performance testing we are currently running into capacity limits on the WFE servers generating a high volume of requests/postbacks from InfoPath forms. We increased the CPU count on each of the 2 WFEs from 8 cores to 12 cores and increased max threads and connections of ASP.NET as such, and were able to gain an additional 20-30% capacity before CPUs again started hitting 100% utilization and requests starting to queue up, response times increasing, and application restarts occurring.

Before looking to scale out more WFEs, we want to scale up existing ones as much as possible first. We are concerned that the single application and worker process will stop scaling at higher core counters. Should we look to web gardening to increase maximum throughput (BLOB caching will be disabled) of the web application/pool?

Answer 1

There are no defined limits as these processes are inherently multi-threaded and can use up to the virtual address space of the edition of Windows that you're using. Web gardens are unsupported.