What is BlazeMeter?
What is Gatling?
Want advice about which of these to choose?Ask the StackShare community!
This is the best open source tool i have ever come across which does load testing at its best.
Python config code is really simple to write and good part is its extendable and there are many hooks available ... what else you need ..
Lastly, the web UI to monitor your swarming activity is too good and very helpful for identify bottlenecks and spikes real-time.