Load Testing Guidelines

Overview#

In order to gather metrics on our system's ability to handle increased loads and users, we have performed tests to evaluate the maximum number of concurrent users a Rasa assistant can handle with certain machine configurations. In each test case we spawned the following number of concurrent users at peak concurrency using a spawn rate of 1000 users per second. In our tests we used the Rasa HTTP-API and the Locust open source load testing tool.

Some recommendations to improve latency#

• Sanic Workers must be mapped 1:1 to CPU for both Rasa Pro and Rasa Action Server
• Create async actions to avoid any blocking I/O
• enable_selective_domain: true : Domain is only sent for actions that needs it. This massively trims the payload between the two pods.
• Consider using compute efficient machines on cloud which are optimized for high performance computing such as the C5 instances on AWS. However, as they are low on memory, models need to be trained lightweight.

Debugging bot related issues while scaling up#

To test the Rasa HTTP-API ability to handle a large number of concurrent user activity we used the Rasa Pro tracing capability along with a tracing backend or collector, such as Jaeger, to collect traces for the bot under test.