BlazeMeter

This is what BlazeMeter - as in "Test your Blaze level" was looking for in their logo design

We provide a performance and load testing solution delivered as a self-service web application for developers and Quality Assurance (QA) professionals.
The service simulates massive load on a web site (emulating thousands of simultaneous users) and then produces reports that let the web site owner see how fast the performance of different elements of the site/application were - and identify potential problems, give optimization recommendations, etc. Read more