Web Application Threads (Demo)

A short story of threads trapped in a job they never wanted

Dependencies

A virtual machine provides the following services:

Service	External port
Graphite	2003
Grafana	3000
Dependency (Wiremock)	8001

From the "vagrant" directory:

• vagrant up starts or create the VM
• vagrant ssh opens a shell into the VM

Inside the Vagrant box:

• wiremock-server start Starts the dependency
• wiremock-server stop Stops the dependency
• dep-delay DELAY Delays the dependency by DELAY milliseconds

Application under test

The application under test is started with ./runApp.sh

It is configured in local.yml to have:

• server
  • acceptor threads: 1
  • selector thread: 1
  • worker threads: 4
• client
  • connection request timeout: 100 ms
  • connection timeout: 100 ms
  • read timeout (socket inactivity): 2000 ms
  • no retries
  • connection pool size: 20

It exposes two endpoints on port 8000:

• GET /sync
• GET /async

Both endpoints call the downstream dependency but use synchronous and asynchronous controllers and services respectively. Outgoing connections are currently not configured, so they use the default configuration.

Performance tests

Simulations are started with:

• ./runSyncSimulation.sh
• ./runAsyncSimulation.sh

Settings in gatling.conf are:

• connection timeout: 100 ms
• request timeout: 3000 ms
• read timeout: 3000 ms
• no retries