EnableSessionState = ReadOnly - possible side effects?

Question

We have a fairly big web based solution which runs on .Net 4.5. Recently, while we were examining a performance issue where the system seemed to be only serving one request

Answer 1

Recently did set sessions to Readonly and it did initially speed up page response performance, we did noticed that any long running posts like a long report from another session would hog up the resources of the entire site, locking up everyone. Our solution was to offload any heavy report processes into a queue to a reporting engine and let the web focus on pages.

However with session set to full, it could distribute the CPU cycles better to each session and bear the brunt of the other heavy session. That was our observation.