This repo helps to explain the difference between synchronous+asynchronous services.
It also shows the dangers/horrors of using TPL in a service.
There are a few branches here that are worth exploring.
You will need to point IIS at the service using the hostname asyncservice.
Don't forget to add a host file entry!
Edit the IIS App Pool to run with ~10 work processes!
This is necessary because the 'request execution limit' is set to 3/10/25 on desktop versions of Windows.
There is a Vagrantfile for running some load testing tools:
vagrant up
vagrant ssh
./attack-ab
./attack-siege
./attack-httperf
Pay particular attention to parallel-and-tpl-walkthrough vs parallel-and-async-walkthrough.
Monitor the locks+threads and concurrent requests in perfmon.